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HEAT
Chapter#11
Multiple choice Questions:
1. The pressure exerted by a column of mercury 76-centimeter high at 0℃ is called: [Q.1 (a)
2002]
*1 liter
*1 𝑐𝑚3
*1 atmosphere *1 𝑁⁄ 2
𝑚
2. A gas exerts pressure on the walls of the container because:[Q.1 (a) 1997]
*The gas molecules collide with each other.
*Gas molecules possess momentum.
*The gas has finite volume.
*The gas molecules attract each other.
3. The temperature at which Centigrade scale coincide with Fahrenheit scale is:[Q.1(a) 1999
,2003& 2007]
*0
*100
*-32
*-40
4. According to kinetic theory of gases, the average translational kinetic energy of a molecule of
an ideal gas is:
1
2
𝟑
* 𝐾𝑇
* 𝐾𝑇
* 𝑲𝑻
* 𝐾𝑇
[Q.1 (a) 1999, 2001]
3
3
𝟐
5. The net change in the entropy of a system in a natural process is
*Zero
* Positive
* Negative
* Infinite [Q.1 (a) 2001]
6. If a substance contracts on freezing (such as Wax), then on increasing the external pressure
on it the freezing point :
*Rises
*Falls
*Remains constant
[Q.1 (a) 1998]
7. The pressure and volume formula of gas undergoing an adiabatic change is
*𝑷𝑽 = 𝒄𝒐𝒏𝒔𝒕𝒂𝒏𝒕
* 𝑃𝛾 𝑉 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
*(𝑃𝑉)𝛾 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
*𝑃𝑉 𝛾 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
[Q.1 (a) 1996, 2004]
8. If the temperature of the cold body is decreased the efficiency of Carnot engine:
*Decrease
* Increase * Remains Constant
[Q.2(a) 1998]
9. 273K = __________.
*0℉
* −32℉
*𝟑𝟐℉[Q.1(a)2000,2003]
10.The pressure exerted by the gas molecule on the walls of the vessel increases if:
*Temperature of the gas decrease
*velocity of the molecules of the gas with its walls increase
*collision of the molecules of the gas with walls decrease
*None of the above happens.
[Q.1 (a) 2001]
11.The K.E of the molecules of an ideal gas at absolute zero temperature will be.
*Infinite
* Zero
*very high *below zero [Q.2(a) 2001]
12.In an isobaric process the work done is equal to:
𝐶𝑝
𝐶
𝑅∆𝑉
* 𝑣
*
*
*𝒏𝑹∆𝑻
[Q.2 (a) 2002 P.M]
𝑛∆𝑉
𝑛∆𝑉
𝑛
13.Choose the correct option.
[Q.1(a) 2002 P.E]
*The product of P and T is constant if volume is constant.
*The ratio of P and V is constant if the temperature is constant.
*The product of P and V is constant if the temperature is constant.
*The product of V and T is constant if pressure is kept constant.
14.The S.I unit of heat is:
*Joules *Calorie
*Centigrade
*Fahrenheit [Q.1 (a) 2002 P.E]
15.Zero on the Celsius scale is equal to:
*273K
*32K
*100K
*212K
[Q.1 (a) 2002 P.E]
16.According to Charles law
[Q.1(a) 2003 P.E]
*PV=constant
*V/T=Constant *VT=Constant
*P/V =Constant
17.The quantity of heat required to raise the temperature of 1 gram of a substance through 1℃
is known as:[Q.1(a) 2003 P.E]
*Specific heat
*Latent heat
*Calorie
*Joules
18.The internal energy in an isothermal process.
[Q.2(a) 2003 P.E]
*Decreases
*Increases
*become zero
*remains constant
19. The maximum efficiency of a heat engine is obtained by:[Q.2 (a) 2003 P.E]
*Increase the temperature of hot body and cold body simultaneous, keeping others factors
constant.
*Decrease the temperature of the sink and increase the temperature of the source,
keeping other factors constant.
*Decrease the temperature simultaneously.*none of these.
19.The change of entropy is given by:
[Q.2(a) 2003 P.E]
∆𝑸
𝑇
∆𝑄
∆𝑈
*∆𝑺 =
*∆𝑆 =
*∆𝑄 =
*∆𝑆 =
𝑻
∆𝑄
𝑇
𝑇
20.One cubic meter is equal to:
[Q.1(a) 2003 P.M & 2006]
𝟔
𝟑
2
3
3
3
*𝟏𝟎 𝒄𝒎
*10 𝑐𝑚
*10 𝑐𝑚
*10−3 𝑐𝑚3
21.If the pressure of the gas is double, keeping the temperature constant, the volume of the gas
is:
[Q.1(a)2003 P.M]
*Reduce to one-fourth
*doubled
*reduced to one-half of the original volume
*Increased four times.
22.According to Charles law.
*V/T= constant when the pressure is constant.
*VT= constant when the pressure is constant.
*PV= constant when the temperature is constant.
*None of these
[Q.2 (a) 2003 P.M]
23.If the volume of the system remains constant, during a process, it is called:
*Isobaric
*Isothermal
*Isochoric *Adiabatic [Q.2 (a) 2003 P.M]
24.Boltzmann constant is equal to:
𝑁
*𝑅𝑁𝐴
*𝑹⁄𝑵
* 𝐴⁄𝑅
* √𝑅⁄𝑁
[Q.2 (a) 2003 P.M]
𝑨
𝐴
25.The coefficient of linear expansion is ____ times the coefficient of volume expansion
*1/3
*3
*None of these
[Q.1(a) 2004]
26.The unit of specific heat is:
*𝑱𝒌𝒈−𝟏 𝑪−𝟏
*𝐽𝑘𝑔−1 𝐾 −1 *𝐽𝐾𝑔𝐶 (d) 𝐽𝐾𝑔𝐶 −1
[Q.2 (a) 2004]
27.RMS velocity of a gas molecule at absolute zero temperature is:
*9 × 106 𝑚/𝑠𝑒𝑐
*3 × 103 𝑚/𝑠𝑒𝑐 *273 𝑚/𝑠𝑒𝑐
* zero
28.The heat required to produce unit change in the temperature of a unit mass of a substance is
called:
[Q.1(a) 2005]
*Heat capacity
*Molar heat
*Specific heat
*Latent Heat
29.The difference between molar specific heat at constant pressure and at constant volume per
mole is called:
[Q.2(a) 2005]
*Heat constant
*Boltzmann Constant
*gas constant
30.A domestic pressure cooker is based on:
[Q.2(a) 2005]
*Adiabatic process
*Isothermal process
*Isochoric process
*Isobaric process
31.The absolute temperature corresponds to 212℉ is:
[Q.2(a) 2005]
*485K
*373K
*161K
*100K
32.In Celsius scale 1℃ in magnitude is equal to:
[Q.1(a) 2006]
*32℉
*16℉ (c) 0℉
(d) 𝟏. 𝟖℉
33.The maximum work done can be measured in the process called:
*Isobaric
*Isochoric
*Isothermal
*Adiabatic [Q.1 (a) 2006]
34.The change in disorder of the system is equal to:
[Q.1(a) 2006]
∆𝑇
∆𝑸
∆𝑇
*∆𝑆 =
*∆𝑺 =
*∆𝑆 =
*∆𝑆 = ∆𝑄.
𝑄
𝑻
∆𝑇
35.In C.G.S system one calorie of heat is equal to:
*11.184 J
*2.184 J
*3.184 J
36.The efficiency of Carnot engine is given by:
𝑇
𝑇
𝑇
*1 − 1
* 1−1
* 2−1
*None of these
𝑇2
𝑇2
[Q.2(a) 2006]
*4.184 J
[Q.2(a) 2006]
𝑇1
37.The volume of a given gas at constant pressure become zero at:
*273𝐾
*273℃
*−273𝐾
*−𝟐𝟕𝟑℃
[Q.1 (a) 2007]
38.The area of a Carnot cycle represents:
[Q.2(a) 2007]
*Energy loss due to leakage
*Heat rejected
*Heat absorbed
*Useful work
39.If the volume of a given mass of a gas is doubled without changing its temperature, the
pressure of the gas is:
*Reduce to ½ of the initial value.
*The same as the initial value.
*Reduce to ¼ of the initial value.
*Double of the initial value.
[Q.1 (a) 2008]
40.A bimetallic thermo state works on the principle of:
*Linear expansion
*Bulk expansion
*Differential expansion *All of these
[Q.1 (a) 2008]
41.The area bounded by an isothermal and an adiabatic curve in a PV diagram for a heat engine
represents:
[Q.2(a) 2008]
*Heat intake *heat rejected
*work done
*total kinetic energy.
42.Entropy has been called degree of disorder because:
*The entropy of universe remains constant
*The entropy of universe always increase
*The entropy of universe always decrease
*None of these
[Q.2 (a) 2008]
43.A thermodynamic process in which the change in volume of the system is zero tell that:
*The work done by the system is maximum
*The work done on and by the system is zero
*The work done on the system is minimum
*None of these
[Q.2 (a) 2008]
44.Heat energy cannot be measured in:
[Q.1(a) 2009]
*J
*B.T.U
*Kelvin
*Calorie
45.Boyle’s law holds good for an ideal gas in a process called:
*Isobaric
*Isochoric *Adiabatic *Isothermal
[Q.1 (a) 2009]
46.According to the second law of thermodynamics 100 percent conversion of heat energy into
work is:
*Possible
*Possible when conditions are not ideal
*Not possible
*possible when conditions are ideal [Q.1 (a) 2009]
47.The molar specific capacities of polyatomic gases as compared to the
Mono atomic gases are:
[Q.2 (a) 2009]
*Greater
*smaller
*equal
*Infinite
48.Thermostat is a device used to keep the:
*Temperature constant
*entropy constant
*Heat constant
*pressure constant
[Q.2 (a) 2009]
49.Two steam engines A and B have their sources at 600℃ and 400℃ and their sinks at 300℃
and 200℃
[Q.1 (x) 2010]
*They are equally efficient
*A is more efficient than B
*B is more efficient than A
50.The maximum work done possible in the process:
[Q.1(i) 2011]
*Isobaric
*Isochoric
*Isothermal
*Adiabatic
51.On Fahrenheit scale the temperature of 50℃ will be:
*40℉
*10℉ * 122℉
* 105℉
[Q.1 (xi) 2010]
52.The kinetic energy per mole of a gas is:
[Q.1(iii)2013]
3
2
𝟑
* 𝐾𝑇
* 𝐾𝑇
* 𝑹𝑻
* 𝑛𝑅𝑇
2
3
𝟐
53.The sum of all energies of molecules in a substance is called:[Q.1(viii) 2013]
*Heat energy
*Temperature
*Kinetic energy *Potential energy
54.The average internal energy of an ideal gas is called:
[Q.1(vii) 2014]
*Pressure
*volume
*Temperature
*Heat
Long Questions
1. What is Carnot’s engine? Describe its construction, working and derive an expression of its
efficiency.(2011, 2009, 2007, 2005, 2002)
2. Write down two statements of second law of thermodynamics and prove their equivalency.
(2010, 2003, 2002)
3. On the basis of kinetic theory of gases, derive an expression for the pressure of a gas. Also
show that the temperature of an ideal gas is directly proportional to the average translational
kinetic energy. Also verify Boyle’s and Charles’s law. (2010, 2009, 2008, 2007, 2006,
2003, 2002)
4. State and explain the first law of thermodynamics. On the basis of the 1 st law explain
isothermal or isobaric process.(2008, 2004, 2002)
Short Questions
1. Using the first-law of thermodynamics in two isotherms of an ideal gas at different
temperatures, show thatCp – Cv = R.
(2011, 2008, 2006, 2004, 2003)
2. Define heat capacity, specific heat and molar specific heat. Write down the mathematical
relations and their units. Establish the equation of relation between the molar specific heat
and common specific heat. (2007, 2006)
3. What do you mean by Entropy? Describe the 2nd law of thermodynamics in terms of
entropy.(2009, 2003)
4.
5.
6.
7.
Define linear expansion. How the concept of linear expansion does helps the fabrication of
bimetallic strips? Explain the working of a bimetallic strip in a thermostat.(2008, 2002)
State the basic assumptions of kinetic molecular theory of the gases.(2007, 2003)
State the gas laws. How are they combined to give the equation of an ideal gas?(2006)
What do you understand by thermal expansion? What is the relation b/w the coefficient of
linear expansion and the coefficient of volumetric expansion? Derive the relation of linear
expansion. (2005, 2004, 2003, 2002)
Numerical from Past Papers:
1. 10 kg of water falls through a distance of 854 meters & all the energy is effective in heating
the water. To what temperature will the water be raised if it was initially at 20 0C.?(1986)
2. The efficiency of the heat engine is 50%.If the temperature of cold reservoir is 300 K, find
the temperature of hot reservoir?(1987)
3. At a certain temperature the average kinetic energy of hydrogen molecule is
6.2 × 10−21 J, the of hydrogen molecule is 3.1× 10−27 𝑘𝑔 find the temperature & root mean
square speed of hydrogen molecule. ( 𝑘 = 1.38 × 10−23 𝐽/𝐾)(1990)
4. A heat engine performs work 0.4166 watt for one hour & rejects 4500 joules of heat energy to
the sink. What is the efficiency of the engine? (1990)
5. A cylinder contains an ideal gas below frictionless piston in it. If the gas in the cylinder is
supplied 300 joules of heat & the piston rise by 0.35 m while the internal energy of the gas
increases by 400 joules. Calculate work done by the piston? (1991)
6. One gram mole of a gas occupies volume of 24.93 m3 at a pressure of 500 N/M2 .Find
temperature of gas in centigrade? (1991)
7. 1200 joules of heat energy are supplied to the system at constant pressure. The internal
energy of the system is increased by 750 joules & the volume by 4.5 cubic meters; find the
work done against the piston and pressure on the piston? (1994)
8. Calculate the r.m.s speed of nitrogen molecule at 270C. Given mass of nitrogen 4.67 ×
10−27 𝑘𝑔 & 𝑘 = 1.38 × 10−23 𝐽/𝐾 (1996)
9. A Carnot engine whose low temperature reservoir is at 200K has an efficiency of 50%. It is
desired to increase this 75% by how much degrees the temperature be decreased, if high
temp reservoir remains at constant temperature? (1997)
10. A 200 gm. piece of a metal is heated to 150 oC and then dropped into an aluminium
calorimeter of mass 500 gm., containing 500 gm. of water initially at 25 oC. Find the final
equilibrium temperature of the system if the specific heat of the metal is 128.100 j/Kg-K,
specific heat of aluminium is 903 j/Kg-k, while the specific heat of water is 4200 j/KgK.(2011)
11. A heat engine performing 400J of work in each cycle has an efficiency of 25%. How much
heat is absorbed and rejected in each cycle?(2010)
12. A scientist stores 22 gm. of a gas in a tank at 1200 atmospheres. Overnight the tank develops
slight leakage and the pressure drops to 950 atmospheres. Calculate the mass of the gas
escaped.(2009).
13. In an isobaric process 2000 J of heat energy is supplied to gas in a cylinder, the piston of area
2.0 X 10-2 m2 moves through a distance 40 cm under a pressure of 1.01X105 N/m2. Calculate
the increase in internal energy of the system.(1996,2009, 2002)
14. A steel bar is 10 m in length at – 2.5 oC..What will be the change the change in its length
when it is at 25 oC?(2008)
15. A Carnot’s engine performs 2000 J of work and rejects 400 J of heat to the sink. If the
difference of temperature between the source and the sink is 85 oC, find the temperature of
the source and the sink and efficiency of engine.(2008 ,2002)
16. Calculate the density of Hydrogen gas, considering it to be an ideal gas, when the root mean
square velocity of Hydrogen molecules is 1850 m/s at 0oC and 1 atmospheric pressure. (2007,
2004, 2002)
17. A heat engine performs work at the rate of 500 kilowatt. The efficiency of the engine is 30%.
Calculate the loss of heat per hour?(1995,2007)
18. Find the change in volume of a brass sphere of 0.6 m in diameter when it is heated from 30 oC
to 100oC. (2006)
19. A Celsius thermometer in the laboratory reads the surrounding temperature as 30oC, what is
the temperature in the Fahrenheit scale and in absolute scale?(2006)
20. A brass ring of 20 cm is to be mounted on a metal rod of 20.02 cm diameter at 20oC. To what
temperature should the ring be heated? (2005, 2002)
21. The low temperature reservoir of a Carnot’s engine is at -30C and has an efficiency of 40%. It
is desired to increase the efficiency to 50%. By how much degree should the temperature
of hot reservoir be increased?
(2004, 2003)
22. An air storage tank whose volume is 110 liters contains 2 Kg of air at a pressure of 15 atm.
How much air would have to be forced into the tank to increase the pressure to 18 atm,
assuming no change in temperature.(2003)
ELECTROSTATICS
Chapter#12
Multiple choice Questions:
1. This is not a scalar quantity
[Q.1(ii)2014;Q.1(xiv)2010&Q.4(a)2007]
*Electric flux
*Electric intensity
*E.M.F
*electric potential
2. Two capacitors of 3𝜇𝐹 and 6𝜇𝐹 are connect in series, their equivalent capacitance is:
*3𝜇𝐹
*9𝜇𝐹
*𝟐𝝁𝑭 * 1⁄2 𝜇𝐹[Q.1(xiv) 2014&Q.1(xii)2010]
3. The number of electrons in one coulomb charge is:[Q.1(ix)2013]
*6 × 1020
* 1.6 × 1018
* 𝟔. 𝟐𝟓 × 𝟏𝟎𝟏𝟖
* 9.1 × 1019
4. If the area of the plates of a parallel plate capacitor is doubled, the capacitance:[Q.1(ii)2013]
*Remained unchanged
*half
*doubled *increased four times
5. The electric intensity between two uniformly opposite charged parallel plates
is:[Q.1(ii)2012&Q.3(a)2004]
𝝈
𝝈
2𝜎
*
*
*
*zero
𝝐𝒐
𝟐𝝐𝒐
𝜖𝑜
6. If an electrostatic force between electrons at a distance is F Newton, if the distance is
doubled the electrostatic force between the two electrons is:
*Zero
*𝑭⁄𝟒
*F
*2F
[Q.1 (iv) 2011]
∆𝑉
7. The relation represents:[Q.1(xii)2011]
∆𝑟
*Gauss’s Law
*electric flux
*Electric intensity
*potential difference
8. Decreasing the separation of two positive charges by one half will cause electrostatic force of
repulsion to change by:
*4 times
*2 times
*1⁄4 𝑡𝑖𝑚𝑒𝑠
* 1⁄4 𝑡𝑖𝑚𝑒𝑠 [Q.1(xii)2010 & Q.3(a)2007]
9. When dielectric placed in an electric field, it becomes:[Q.3(a)2009]
*Negatively charged only
*positively charged only
*polarized
*conductive
10.The capacitance of parallel plate capacitor does not depends upon:
*Area of the plate
*distance between the plates
*nature of the plates
*medium between the plates [Q.3 (a) 2009]
11.The change in potential energy per unit charge between the two points in an electric field is
called:[Q.4(a) 2009]
*Intensity
*flux
*potential difference
*permittivity
12.The introduction of dielectric between the oppositely charged plates causes the
intensity:[Q.3(a)2008]
*To increase
*to decrease
*to increase and decrease
*to remain constant
13.Two oppositely point charges repel each other with a force of 4 × 10−4 𝑁 when placed at a
distance of 1 meter. If the distance between them increased by 2m, the force of repulsion will
be:[Q.3(a)2008 ]
*𝟏 × 𝟏𝟎−𝟒 𝑵
*4 × 10−4 𝑁 * 8 × 10−4 𝑁
* 2 × 10−4 𝑁
14.Electric flux through the surface of a sphere which contains a charge at its center depends
on:[Q.4(a) 2008]
*The radius of the sphere
*the amount of charge inside the sphere
*The surface area of the sphere
*the amount of charge outside the sphere
15.Coulomb/Volt is the unit of :
[Q.3(a) 2007]
*resistance
*capacitance
*resistivity *current
16.which of the following cannot be a unit of electric intensity:[Q.4(a)2007&Q(a)2002]
*𝑁/𝐶𝑜𝑙𝑜𝑚𝑏 *volt/meter *joules/coulomb *joules/coulomb-meter
17.Two capacitors of 4𝜇𝐹 and 2𝜇𝐹 are connect in series, their equivalent capacitance is:
*𝟏. 𝟑𝟑𝝁𝑭
*0.75𝜇𝐹
*6𝜇𝐹
* 2𝜇𝐹
[Q.3(a)2006]
18.The quantity ∆𝑉/∆𝑆 is called:[Q.4(a)2006]
*Electric potential *potential gradient *electric field intensity *electric induction
19.The concept of electric line of force was introduce by the famous scientist called:
*Newton *Einstein *Coulomb
*Faraday [Q.5(a)2006]
20.One joule per coulomb is called:[Q.5(a) 2004&Q.6(a)2002]
*Farad
*Gauss
*Ampere *Volt
21.The presence of the dielectric between the plates of a capacitor results in:
*Increase in the capacitance *decrease in the capacitance
*no change in the capacitance
*none of them [Q.3 (a) 2003P.E&P.M; Q.6 (a) 2002]
22.The change in potential energy per unit charge between two points in an electric field is
called:[Q.3(a)2003]
*Electric intensity *permittivity
*potential difference *Absolute potential
23.If two capacitors of 5𝜇𝐹 and 7𝜇𝐹 are connected in parallel, their equivalent capacitance
in:[Q.3(a)2003]
*0.12𝜇𝐹
*𝟏𝟐𝝁𝑭
* 0.34𝜇𝐹
* 2.9𝜇𝐹
24.The force per unit charge is known as:[Q.3(a)2002]
*Electric flux
*electric field intensity
*electric potential
*electric current
If the 4𝜇𝐹 and 2𝜇𝐹 capacitors are connected in series the equivalent capacitance
is:[Q.2(a)2002]
*0.75𝜇𝐹
*6𝜇𝐹 *2𝜇𝐹 *𝟏. 𝟑𝟑𝝁𝑭
25.The electric intensity between two similar charge plates is:[Q.3(a)2002]
𝝈
𝜎
2𝜎
*
*
*
* zero
𝝐𝒐
2𝜖𝑜
𝜖𝑜
26.The electric flux through a surface will be minimum, when the angle between 𝐸⃗ and ∆ 𝐴
is:[Q.3(a) 2002]
*𝟗𝟎𝟎
*0𝑜
* 450
*600
Long Questions
1. State Gauss’s law. Apply the law to find electric field intensity due to a uniform metallic
charge sphere at a point “P” lying outside the charge sphere(2012)
2. What is a capacitor? Derive the expression for the capacitance for the parallel plate capacitor
when (i) Air exist between the plates (ii) Space between the plates is partially filled by a
dielectric medium.(2011,2008, 2005, 2003)
3. State Gauss’s law. Apply it to find out the electric field intensity due to a thin sheet of
positive charge.(2010, 2008, 2006, 2004, 2002)
Short Questions
1. Derive a relation for equivalent capacitance of a capacitor when three capacitors are
connected in series.(2009)
2. State the electric flux. Under what conditions will the flux through the surface be? (i) zero (ii)
maximum (2007)
3. Define electric potential. Derive a relation between electric potential and electric field. (2004)
4. Derive a relation of an equivalent capacitance when three capacitors connected in series.
(2003)
5. State and prove Gauss’s law. (2003)
6. Derive a relation of an equivalent capacitance when three capacitors connected in parallel.
(2002)
Numerical from Past Papers:
1. Two capacitors of 2.0µF & 8.0µF capacitance are connected in series & a potential difference
of 200 volts is applied. Find the charge & the potential difference for each capacitor? (1990)
2. An oil drop having a mass of 0.002 milligram & charge of 6 electrons charge suspended
stationary in a uniform electric field. Find the intensity of electric field.(1990)
3. Calculate the potential difference between the two plates when they are separated by the
distance of 0.005 m & are able to hold an electron motionless between them.(1991)
4. Find the equivalent capacitance & charge on 5µF capacitor shown in diagram (1993)
5. Two horizontal metallic plates separated by a distance of 0.5 cm are connected with a battery
of 10 volts. Find electric field intensity between the plates & the force on a proton placed
between the plates.(1994)
6. Two capacitors of capacitance 4.00µF & 6.00µF are charged to the potential difference of
300 volts & 400 volts respectively. They are then connected in parallel. What will be the
resultant potential difference & charge on each capacitor? (1995)
7. A thin sheet of positive charge attracts a light charged sphere having a charge
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
−5 × 10−6 C with a force 1.695N. Calculate surface charge density? (1996)
A capacitor of 200 pF is charged with 100 volts. Its plates are then connected in parallel to
another capacitor & are found that the P.D between the plates falls to 60 volts. What is the
capacitance of the second capacitor? (1997)
A capacitor of 12µF is charged with 100 volts. Its plates are then connected in parallel to
another capacitor & are found that the P.D between the plates falls to 60 volts. What is the
capacitance of the second capacitor? (2008)
Calculate the force of repulsion on 2× 10−8 𝐶 charge, if it is placed before a large vertical
charged plate whose charge density is 20× 10−4 𝐶 2 /𝑁 − 𝑚2 . (1998)
A charged particle of 17.7µC is placed close to a positively charged thin sheet having charge
density 2× 10−6 𝐶 2 /𝑚2 . Find the magnitude & direction of force acting on the charged
particle. (2000)
A parallel plate capacitor has plates 10𝑐𝑚 × 10𝑐𝑚 separated by a distance of 2.5cm initially
filled with air. What will be the increase in the capacitance if a dielectric slab of same area &
thickness 2.5cm is placed between the two plates? (2001)
A small sphere of weight 0.005N is suspended by a silk thread which is attached to a point on
a large charged insulating plane. When a charge of 𝟔 × 𝟏𝟎−𝟖 𝑪 is placed on the ball the thread
makes an angle of 𝟑𝟎𝒐 with the vertical; find the charge density on the plane? (2002)
A particle carrying a charge of 𝟏𝟎−𝟓 𝒄 starts from rest in a uniform electric field of intensity
𝟓𝟎 𝑽⁄𝒎.Find the force on the particle and K.E when it move 1m. (2003)
How many excess electrons must be placed on each of two similar spheres placed 0.3cm apart
if the force of repulsion between the spheres is 10-19N.(2007)
Two point charge +𝟐 × 𝟏𝟎−𝟒 and −𝟐 × 𝟏𝟎−𝟒 coulomb are placed at a distance of 40cm from
each other. A charge of +𝟓 × 𝟏𝟎−𝟓 coulomb is placed midway between them. What is
𝟐
magnitude and direction of force on it? (𝑲 = 𝟗 × 𝟏𝟎𝟗 𝑵𝒎 ⁄ 𝟐 )(2012)
𝒄
−𝟏𝟕
−𝟏𝟗
A proton of mass 𝟏. 𝟔𝟕 × 𝟏𝟎 𝒌𝒈 and charge 𝟏. 𝟔 × 𝟏𝟎 𝒄 is to be held motionless
between two parallel horizontal plates. Find the distance between the plates when the
potential difference of 𝟔 × 𝟏𝟎−𝟗 𝒗𝒐𝒍𝒕 is applied across the plates.(2011, 2009)
How many electrons should be removed from each of two similar spheres each of 10 gm. so
that electrostatic repulsion may be balanced by gravitational force.(2010,200)
A capacitor of 𝟏𝟐µ𝑭 is charged to a potential difference 100V. Its plates are then
disconnected from the source and are connected parallel to another capacitor. The potential
difference in this combination comes down to 60V. What is the capacitance of second
capacitor?(2009)
CURRENT ELECTRICITY
Chapter#13
Multiple choice Questions:
1. Which one of the quantity is analogous to temperature in electricity
*Resistance *potential difference
*current *charge
2. Which one is the property of a material
*Resistance *current
*E.M.F
*resistivity
3. Resistance of a conductor increases with the rise of temperature of a conductor. This is due
to
*Increases of electron density *decreases of drift velocity of electrons
*Increases number of free electrons per unit volume
*decreases in potential difference
4. The resistance of a wire is R ohms. If the wire is stretched to double its length, its resistance
will become.
*𝟐𝑹
*R/2
*R/4
*4R
5. A potential difference of V volt is applied across a parallel combination of two resistors of
resistance R ohms each which of the following relations is true if total current is I
𝑉
𝑉
*𝑉 = 𝐼1 𝑅 + 𝐼2 𝑅
*𝑉 = 𝐼𝑅/2
*𝐼 = 𝐼1 + 𝐼2 *𝐼 = 1 + 2
𝑅
𝑅
6. The internal resistance of 6V battery is 0.3 ohm. A current of 2 A is drawn from it by
connecting a resistor of 2.7 ohm. A voltmeter indicate which of the volt
*4.8V
*5.4V
*6V
*none of these
7. The S.I unit of resistivity is
𝛺
*𝛺 −1 𝑚−1 *𝛺𝑚−1
*𝜴𝒎
*
𝑚
8. According to Ohm’s law I =
2
*𝑽⁄𝑹 * 𝑉⁄ 2
* 𝑉 ⁄𝑅
* None of these
𝑅
9. When temperature rises the resistance of insulators and semiconductors
*Remains same *rises *decreases *none of these
10.The reciprocal of resistance is called
*Capacitance
*admittance *conductance
*inductance
11.KWh is the unit
*Power
*energy
*electric field
*potential difference
12.The unit of temperature coefficient of resistivity is
*℃−𝟏 *𝑚℃−1
*𝑚−1 ℃−1 *None of these
13.Cells and batteries are the sources of current
*Alternating current
*Direct current
*both
*none of these
14.The power dissipated in a resistance is [2005]
𝑉2
*VI
*I2R
*
*all of them
𝑅
15.The commercial unit of electrical energy is [2010]
*ohm
*watt
*kilowatt-hour *ampere
16.The electrical energy dissipated as heat in a resistor is given by [2010]
*I2R
*I2RT
*V2R
*V2RT
17.Two wires of resistance R1 & R2 are connected in a series circuit, if R1 is greater than R2
then heating would be[2011]
*more in R1
*more in R2
*same in both
*all of these
18.A copper wire having resistivity P is stretched in such a way that if diameter reduces to half
o half of that of the original wire. The new resistivity will be
*halved
*doubled *the same *four fold
[2011]
19.Resistors of 2Ω, 3Ω, 4Ω & 5Ω are connected in series. If the current flowing through 2Ω
resistor is 1ampere, the current flowing through the other resistors will be[2012]
*4 amperes
*6 amperes
*1 amperes
*0.1amperes
20.Resistors of 3Ω, 5Ω &7Ω are connected in parallel. If the P.D across 5Ω resistor is 6 volts,
the P.D across the other resistors is [2013]
*4 volts
*6 volts
*8 volts
*10 volts
21.Resistance of a wire does not depend on the: [2014]
*temperature
*length
*area
*electric current
22.Joules per coulomb is called: [2012,2014]
*Farad
*Ampere *Volt
*Henry
Short Questions
1. Define potential difference and electromotive force. Both are measure in volts. What is the
difference between these concepts? (2010, 2002)
2. Differentiate between terminal potential difference and EMF of a battery. Derive the relevant
expression.(2008)
3. State Ohm’s laws and derive an expression for the equivalent resistance of three resistors
connected in series. (2006)
4. Define a resistance and write its unit. How the resistance does depend upon the temperature?
Derive an expression for the resistance at the given temperature. (2005,2003)
5. Define Ohm’s law and give its limitations? (2004)
6. How is the resistance of a metallic conductor affected by variation in temperature? (2011)
7. Define Ohm’s law. Define resistivity and name the factor on which the resistance depends.
(2002)
Numerical from Past Papers:
A platinum wire of diameter 0.2mm is wound to make a resistor of 4Ω. How long a wire is
needed? (1995)
Ans 1.42m
2. You are given three resistors each of 2Ω. How would you arrange these resistors to obtain the
equivalent resistance of (i) 0.067Ω (ii) 3Ω (iii) 6Ω(2000)
3. Find the equivalent resistance & current through resistor R3 & R4.(2001)
4. Two resistors of 10Ω& 50Ω are connected in series with a 6 volt battery. Calculate the charge
drawn from the battery per minute & power dissipated in 10Ω resistor. (2005)
5. A water heater that will deliver 1Kg of water per minute is required. The water is supplied at
𝟐𝟎℃ and an output temperature of 𝟖𝟎℃ is desired. What should be the resistance of the
heating element in water if the line voltage is220V? (𝒔𝒑𝒆𝒄𝒊𝒇𝒊𝒄𝒉𝒆𝒂𝒕𝒐𝒇𝒘𝒂𝒕𝒆𝒓 =
𝑱
𝟒𝟐𝟎𝟎 ⁄𝒌𝒈℃)(2010)
6. A resistance is made by using a 50m nichrome wire of diameter 0.8 mm at𝟎℃. Calculate its
resistance at 𝟓𝟎℃(𝝆 = 𝟏. 𝟏 × 𝟏𝟎−𝟔 Ω𝒎𝒂𝒏𝒅𝜶 = 𝟎. 𝟎𝟎𝟎𝟐℃−𝟏 )(2009)
7. A rectangular bar of iron is 𝟐𝒄𝒎 × 𝟐𝒄𝒎 in cross-section and 20cm long. What is the
resistance of the bar at 𝟓𝟎𝟎℃ if𝝆 = 𝟏𝟏 × 𝟏𝟎−𝟖 Ω 𝒂𝒏𝒅𝜶 = 𝟎. 𝟎𝟎𝟓𝟐𝑲−𝟏 ?(2013)
8. A 50 ohm resistor is required from a copper wire, 0.2mm in diameter. What is the length of
the wire needed? (2006)
9. A 50 ohm resistor is to be wound with the platinum wire, 0.1mm in diameter. How much wire
is needed? (2003)
10. A battery of 24V is connected to a 10 ohm resistor (load) and a current of 2.2 amps is drawn;
find the internal resistance of the battery and its terminal voltage? (2002)
11. The resistance of a tungsten wire used in the filament of a 60w bulb is 240 ohm when the
bulb is hot at temperature os2020℃ , what would you estimate its resistance at 20℃?(2002)
1.
MAGNETISM AND ELECTROMAGNETISM
Chapter#14
Multiple choice Questions:
1. An electron & a proton with the same momentum enter perpendicularly into a uniform
magnetic field
*Both particles will deflect equally
*the proton will deflect more than electron
*The electron will deflect more than proton [1996, 2002]
2. The maximum magnetic force will act on a current carrying conductor in a magnetic field
when it is placed:[2001]
*At 600 to the field
*parallel to the field
*perpendicular to the field
*at 450 to the field
3. The current produced by moving the loop of a wire across the magnetic field is
called:[2001]
*electric current *A.C current
*D.C current
*induced current
4. The force experienced by a current carrying conductor when it is placed in a magnetic field
is :[2001]
⃗ ×𝐵
⃗)
⃗ = 𝑰(𝑳
⃗ × ⃗𝑩
⃗)
⃗)
*𝐹 = 𝐼(𝑉
*𝑭
*𝐹 = 𝐵(𝐿⃗ × 𝐼 )
*𝐹 = 𝐿(𝐼 × 𝐵
5. Which of the following is scalar
*Magnetic flux
*magnetic flux density *E.M.F
*both (a) and (c)
6. The north pole of a magnet is moved away from a metallic ring. The current in the metallic
ring flows in
*Clock wise
*First clock wise and then anti-clockwise
*Anti-clockwise
*First anti-clock wise and then clock wise
7. The frequency of A.C mains in Pakistan is 50Hz, so the number of times the A.C changes
its direction is
*50 *100 *25 *60
8. The energy reside in a current carrying conductor in the form of
*Magnetic field
*electrostatic field
*thermal vibration *both (b) and (c)
9. If positively charge particles enter with high velocity from the sky towards the earth, then
the earth magnetic field deflect it towards
*East
*West
*North
*South
10.Which of the following is analogous to mass in electricity?
*Charge
*Inductance
*capacitance
*potential
11.A coil having N turns and area A is rotated in the magnetic field B with angular velocity ω,
then the maximum E.M.F induces in it is.
𝑁𝐴
𝑁𝐵𝐴
ω
*
*
*
*NBAω
𝐵ω
ω
𝑁𝐵𝐴
12.Transformer is used in circuits containing
[2010]
*D.C alone *A.C alone *Both A.C and D.C
*non-inductive winding
13.A long solenoid that has been bent into a circle is called
*Resistor *Capacitor *Toroid
*None of these
14.The practical application of mutual induction is
*Generator
*Motor
*Transformer
*Circuit breakers
15.When an electric current passes through a conductor produces around it
*An electric filed
*a magnetic field
*both electric and magnetic fields *none of these
[2002]
16.The core of transformer is laminated to reduce the loss of energy caused by
*Flux leakage
*Eddy current *Heating *All of these
17.If the number of turns in the coil is double then its self-inductance will be
*Half
*Double
*same
*forth-fold
18.Transformer works on the principle of
[2002]
*OHM’s Law
*self-induction
*mutual induction
*Gauss’s Law
19.The deflecting torque on a current carrying coil placed in a magnetic field is maximum
when the angle between the magnetic field & the plane of the coil is
*zero
*900
*600
*450
[2002]
20.When north pole of a bar magnet approaches the face of a closed coil the face
becomes:[2003]
*south Pole *first north & then south
*North Pole *no effect
21.S.I unit of induction is
[2005]
*tesla
*henry
*watt
*weber
22.The motional E.M.F induced in a coil is independent of
[2010]
*change of flux *number of turns
*time
*resistance
23.The path of a neutron moving normal to a magnet field is
[2005]
*straight line
*oval
*circular
*sinusoidal
24.The maximum resistance in an A.C circuit is offered by
[2005]
*capacitor *solenoid *electromagnet
*electric bulb
25.The direction of induced current is given by
[2005]
*ampere’s law
*faraday’s law
*lenz’s law *snell’s law
26.Tesla (T),the unit of B is
[2004]
𝑛𝑒𝑤𝑡𝑜𝑛
𝒏𝒆𝒘𝒕𝒐𝒏
𝑎𝑚𝑝𝑒𝑟𝑒
𝑎𝑚𝑝𝑒𝑟𝑒×𝑚𝑒𝑡𝑒𝑟
*
*
*
*
𝑐𝑜𝑢𝑙𝑜𝑚𝑏×𝑚𝑒𝑡𝑒𝑟
𝒂𝒎𝒑𝒆𝒓𝒆×𝒎𝒆𝒕𝒆𝒓
𝑛𝑒𝑤𝑡𝑜𝑛×𝑚𝑒𝑡𝑒𝑟
𝑛𝑒𝑤𝑡𝑜𝑛
27.In step down transformer
[2003]
*Ns >Np *Ns <Np *Ns = Np *none of these
28.One tesla is equal to
[2003]
2
2
2
*weber/meter
*2weber/meter
*weber /meter
*newton/ampere
29.When a charged particle enters a uniform magnetic field perpendicularly its path is
*spiral
*circular
*parabolic *straight line
[2002]
30.If a straight conductor of length ‘L’ carrying a current ‘I’ is placed parallel to a magnetic
field ‘B’ the force experienced by the conductor
*BIL
*BILSinθ
*zero
*infinite
[2002, 2005]
31.A device which convert mechanical energy into electric energy is called
*Motor
*Transformer
*generator
*none of these
Long Questions
1. Describe a method to determine the ratio of charge to mass of an electron. Derive the relevant
mathematical expression? (2012, 2010, 2005, 2003)
2. State Faraday’s laws of electromagnetic induction. Explain the phenomena of mutual
induction, and derive an expression for mutual inductance of two coils, also give its unit?
(2012, 2011, 2007, 2004)
3. What is transformer? Name its components and describe its working? (2011, 2008, 2003)
4. What is the difference between magneto and A.C generator? What is mean by the frequency
of A.C current? Prove mathematically that the radius of circular path for a charge move in a
magnetic field is given as 𝒓 = 𝒎𝒗⁄𝒒𝒃 𝐬𝐢𝐧 𝜽 where all symbols have their usual meanings.
(2011)
5. State Ampere’s law and derive an expression for the magnetic field for a long solenoid?
(2011, 2009, 2003)
6. Draw a labeled diagram of an A.C generator and derive an expression for the alternating
voltage produce. (2010, 2004)
7. State Ampere’s law and derive an expression for the magnetic field for a long toroid? (2008)
Short Questions
1. In what way the motional emf, produced in a conductor placed in a magnetic field, translated
into the relevant mathematical expression? (2012, 2008, 2003)
2. Derive an expression for the force on a current carrying conductor placed in a uniform
magnetic field? (2011, 2008, 2006, 2004)
3. Derive a relation for a torque due to a current carrying coil in a magnetic field. (2010, 2005)
4. Describe the phenomena of self-induction and define self-inductance of the coil, give its unit?
(2009)
5. Define magnetic field. Derive an expression for the magnitude of magnetic field of induction
B, give its unit? (2004)
Numerical from Past Papers
1. Current of 2 amperes passess through an inductive circuit. What is the self-inductance of the
circuit if the current falls to zero in 0.1 sec. when the average value of induced EMF is 20.0
volts?(1985)
(1.0 henry)
2. A toroid coil has 300 turns & mean radius 12cm. calculate the magnetic field of induction B
inside the coil when a current of 5 amperes passes through it. (1985)
Ans2.5 ×
−3
2
10 𝑤𝑒𝑏𝑒𝑟/𝑚
3. A train is moving with a speed of 10 m/sec. if the vertical component of the earth’s magnetic
field of induction is 5.4 × 10−3 𝑤𝑒𝑏𝑒𝑟/𝑚2 compute the EMF induced in 1.2m long
axle.(1986)
(Ans 6.48× 10−4 𝑣𝑜𝑙𝑡𝑠)
4. An electron having a speed of 1.6 × 106 𝑚/𝑠𝑒𝑐 is moving along a circle of radius 1.82 ×
10−6 𝑚 on entering perpendicularly in a magnetic field. Find the value of the magnetic field.
(1987)
(Ans5.01𝑤𝑒𝑏𝑒𝑟/𝑚2 )
5. A transformer has 1000 turns in its primary coil. If the input voltage of the transformer is 200
volts, what should be the number of turns of the secondary coil to obtain an output of 6.0
volts? (1992)
(Ans 30 turns)
6. A current of 2.00 amperes is passing through a solenoid. If the solenoid has 24 turns per cm
of its length, find magnetic field? (1992)
(Ans6.03 × 10−3 𝑤𝑒𝑏/𝑚2 )
7. A coil having an area of cross section 0.05 m2& number of turns 100 is placed perpendicular
to the magnetic field of induction 0.8𝑤𝑒𝑏/𝑚2 . How much EMF will be induced in it if the
field is reduced to 0.02 𝑤𝑒𝑏/𝑚2 in 0.01 sec? (1993) (Ans 30 volts)
8. A 10 ev electron is moving in a circular orbit in a uniform magnetic field of strength 10-4
weber/m2 . calculate the radius of circular path?(1993,1999)(Ans 0.107m)
9. An electron is moving along on a circle of radius1.8 × 10−7 𝑚. Calculate speed of the
electron on entering perpendicularly in a uniform magnetic field of 5.0 tesla? (1995,2002)
(Ans 1.581× 105 𝑚/𝑠)
10. Α particle is accelerated from rest at a P.D of 1kV. They then enter a magnetic field 𝐵 =
0.2 𝑇 perpendicular to their direction of motion. Calculate radius of path.(1997)
11. A 500 turn’s coil in an A.C generator having an area of 1000 cm2 rotates in a magnetic field
of value 50 tesla. In order to generate 220 volts maximum, How fast is the coil to be rotated
in revolutions per second?(1998)
(Ans 0.014 revolution/sec)
12. A transformer has 1000 turns in the primary coil. If the input voltage of the transformer is 200
volts, What should be the number of turns of the secondary coil to obtain an output voltage of
6.0 volts?(1999)
(Ans 30 turns)
13. What will be the mutual inductance of two coils when the change of current of 3 amperes in
one coil produces the change of flux of 6 × 10−4 webers in the second coil having 2000
turns?(2001)
(Ans 0.4 henry)
14. An electron is accelerated by the potential difference of 100 volts. It then enters into a
uniform magnetic field of induction 𝐵 = 2.5𝑤𝑒𝑏/𝑚2 at an angle of 450 with the direction of
the field. Find the radius of path described by the electron.(2001)(Ans 1.91× 10−5 𝑚)
15. A long solenoid is wound with 10 turns per cm. & carries a current of 10 amperes. Find
magnetic flux density in it? (2001)
(Ans𝐵 = 1.248 × 10−2 𝑤𝑒𝑏/𝑚2 )
16. An EMF of 45 millivolts is induced in a coil of 500 turns, when the current in a neighboring
coil changes from 10 amperes to 14 amperes in 0.2 seconds. Find the mutual inductance of
the coil & rate of change of flux in the second coil? (2002)(Ans 2.25mh,9× 10−5 𝑤𝑒𝑏/𝑠)
17. A step down transformer has 4000 turns in its primary coil. If the input voltage of the
transformer is 4400 volts, what should be the number of turns of the secondary coil to obtain
an output of 220volts.if the efficiency of the transformer is 90% and 9KW power is required
determine the input power and current in the primary and secondary coil? (2005) (Ans 200
turns,10KW,2.273ampere)
18. A proton accelerated through 1000 volts is projected normally to a 0.25 tesla magnetic field.
Calculate the kinetic energy on entering the magnetic field & radius of circular path of
proton. (2005)
19. Find the current required to produce a magnetic field of induction 𝐵 = 2.512 × 10−3 𝑤𝑒𝑏/
𝑚2 in a 50 cm long solenoid of 4000 turns of wire? (2012, 2011,1990)
20. An alternating current generator operating at50 Hz has a coil of 200 turns, while coil has an
area of 120 cm2. Calculate the magnetic field intensity applied to rotate the coil to produce
the maximum voltage of 240V? (2011)
21. The inner and outer diameter of the Toroid is 22cm and 26cm. If a current of 5 A is passed
which produces 0.025 tesla flux density inside the core. Find the approximate length of the
wire wound on the toroid? (2011)
22. A pair of adjacent coil has a mutual inductance of 850mH. If the current I primary coil
changes from 0 to 20A in 0.1 sec, what is the change in magnetic flux in the secondary coil of
800 turns? (2009)
23. A step down transformer reduces 1100V to 220V. The power output is 12.5KW and the
overall efficiency is 90%. The primary winding has 1000 turns, how many turns do the
secondary have? What is the power input? What is the current in each coil? (2008, 2005)
24. An aero plane is flying in a region where the vertical component of earth magnetic field
is𝟑. 𝟐 × 𝟏𝟎−𝟒 𝒕𝒆𝒔𝒍𝒂. If the wing span of the aero plane 50m and its velocity is 360 𝒌𝒎⁄𝒉𝒐𝒖𝒓
find the induce emf between the tips of the wings of the aero plane? (2007)
25. A long solenoid is wound with 35 turns in 10cm, and carries a current 10A. Find the magnetic
field in it?
26. A long solenoid of cross section area of 5.0cm2 is 25.0cm long wound with 250turns, and
carries a current 5A. Find the magnetic field in it? (1994) (Ans6.283 × 10−3 𝑤𝑒𝑏𝑒𝑟/𝑚2 )
27. A long solenoid of diameter 5.0cm is 25.0cm long wound with 250turns, and carries a current
5A. Find the magnetic field in it? (1988)
(Ans6.283 × 10−3 𝑤𝑒𝑏𝑒𝑟/𝑚2 )
28. How fast must a proton of mass 𝟏. 𝟔𝟕 × 𝟏𝟎−𝟐𝟕 𝒌𝒈 be moving if it is to follow a circular path
of radius 2cm in a magnetic field of 0.7 tesla? (2004)
29. The current in a coil of 500 turns is changed from zero to 5.43A. Thereby producing a
magnetic flux 𝟖. 𝟓𝟐 × 𝟏𝟎−𝟒 weber. What is the self inductance of the coil? (2004)
30. A coil of 50 turns is wound on ivory frame 𝟑𝒄𝒎 × 𝟔𝒄𝒎 which rotates in a magnetic field of
induction𝑩 = 𝟐𝒘𝒆𝒃/𝒎𝟐 . What will be the torque acting on it if a current of 5A passes
through it and the planes of the coil make an angle of 𝟒𝟓𝒐 with the field? (2003)
ELECTRICAL MEASURING INSTRUMENT
Chapter#15
Multiple choice Questions:
1. An Electrical instrument which is used to detect small current is
*Galvanometer *Voltmeter *Meter Bridge
*None of these
2. To increase the accuracy in a potentiometer circuit:[1997]
*a wire of small length is used
*a wire of large length is used
*a non-uniform wire is used
*none of these
3. All the electrical appliances are connected in parallel to each other between the main line &
neutral wire to get:[2001]
*the same current
*the same potential difference
*difference current & same potential difference
*none of the above
4. Galvanometer can be converted into ammeter by connecting:[2002]
*low resistance in Series
*high resistance in Parallel
*low resistance in parallel
*high resistance in series
5. Galvanometer can be converted into voltmeter by connecting a high resistance in
*Series
*Parallel
*Internal circuit
*External circuit
6. Post Office box works on the principle of
*Generator *Motor
*Transformer
*Wheatstone bridge
7. A meter Bridge is used to measure:[2002,2013]
*Capacitance
*Resistance
*Voltage *inductance
8. AVO meter is used to measure:[2002,2012]
*current
*voltage
*resistance *all of them
9. For a moving coil galvanometer, the current must be proportional to
*Resistance *Voltage *Capacitance
*Deflection
10.The low value of resistance used to convert galvanometer into ammeter is also termed
as______________ resistance
*Shunt
*Multiplier *Reciprocal
*Negative
11.A single device containing ammeter, voltmeter & ohmmeter is called:
*VTVM
*multi-meter
*CRO
*potentiometer
[2010]
12.__________ is the device which can measure current, Voltage and resistance
*Geiger counter *AVO meter
*Cathode Ray tube
13.Potentiometer is a device which is used to measure ___________ [2003]
*Potential difference
*EMF
*voltage between the two points
*all of these
14.To measure electric current through the circuit, ammeter must be connected in _______.
*Series
*Parallel
*In any mode
*None of these
15.To measure potential difference through the circuit, voltmeter must be connected in
*Series
*Parallel
*In any mode
*None of these
16.This is a high resistance instrument
[2014]
*voltmeter
*ammeter
*galvanometer
*motor
17.Concave magnetic pole of galvanometer makes the field__________.
*Radial
*Normal
*Tangential *All of the above
Past Paper Questions:
1. Give the construction and working of a moving coil galvanometer. Show that current I is
directly proportional to the angle of twist. On what factors does the sensitivity of
galvanometer depend? (2009, 2011, 2006, 2002)
𝑹
𝑹
2. Describe Wheatstone bridge. Prove that for a balanced Wheatstone bridge 𝟏 = 𝟑
𝑹𝟐
𝑹𝟒
(2008, 2010, 2006, 2002)
3. Describe the conversion of galvanometer into a voltmeter and ammeter. (2007, 2005, 2004,
2003)
Numerical from Past Paper:
1. A moving coil galvanometer has a resistance of 50 ohms & gives full scale deflection for a
P.D of 150 millivolts. What should be the resistance of the shunt used in order to use it as an
ammeter reading up to 4.0 amperes?(1987)
(Ans 0.0375Ω)
2. A galvanometer of resistance 50 ohms gives full scale deflection with a current of
0.005A.What will be the resistance of the instrument to measure a current of 1.00A. (1989)
(Ans 0.25Ω)
3. A galvanometer of resistance 60 ohms gives full scale deflection with a current of 4mA. A
resistance of 10940 ohms is connected in series with the coil to convert it into voltmeter, find
the range of voltmeter obtained? (1995) (Ans 44 volts)
4. A moving coil galvanometer has a resistance of 25 ohms & gives full scale deflection for a
P.D of 5 millivolts. What should be the resistance of the series resistance used in order to
convert it into voltmeter reading up to 50 volts?(1997)
(Ans 249975Ω)
5. A moving coil galvanometer has a resistance of 50 ohms & gives full scale deflection for a
P.D of 100 millivolts. What should be the resistance of the series resistance used in order to
convert it into voltmeter reading up to 50 volts?(2000) (Ans 24950Ω)
6. The coil of a galvanometer having a resistance of 50 ohms, a current of 500 microampere
produces full scale deflection in it. compute (i) the shunt required to convert it into an
ammeter of 5 ampere range.(ii) the series resistance required to convert it into a voltmeter of
300 volts.(2002)
(Ans 0.005Ω,599950Ω)
7. A galvanometer whose resistance is 50 ohm deflects full scale for a potential difference 100
mV across its terminals. How can it be converted into a voltmeter of 50 V range?
(2010)
8. A galvanometer has a resistance of 100 ohms and potential difference of 50 mV gives the full
scale deflection. Calculate the shunt resistance to read from 0--5A. What is the value of the
series resistance if the galvanometer is to be converted into a voltmeter to read up to 250 V?
(2008)
9. A 300 V voltmeter has a total resistance of 20 kilo-ohms. What additional series resistance is
required to convert it into a voltmeter ranging up to a maximum of 600 V volts? (2007, 2004,
2003, 2002)
10. An ammeter deflects full-scale with a voltage of 2.5 volts, and has a total resistance of 0.5
ohm. What small resistance must be connected to measure 20 A Full scales? (2006, 2002)
11. A maximum 50 mA current can be allowed to flow through a 19.8 ohm coil of a
galvanometer. The galvanometer is to be used to measure 5A maximum current. Calculate the
length of copper wire to be used as a shunt. The diameter of wire is 4mm. (resistivity of
copper is 1.6 × 10−4 Ω𝑚,2005)
(1.57cm)
12. An ammeter deflects full scale with a current of 5A and has a total resistance of 0.5 ohm.
What shunt resistance must be connected to it to measure full scale current up to 30A? (2003)
ELECTROMAGNETIC WAVES AND ELECTRONICS
Chapter#16
Multiple choice Questions:
1. _________ is a device which is fabricated by combining P & N type material.
*Transistor *Diode
*Voltmeter
*Ammeter
2. The conversion of A.C into D.C is called
*Rectification
*Amplification
*Modulation
*All of these
3. A semi-conductor diode can be used as a/an [2002,2003]
*rectifier *Amplifier *Oscillator *Switch
4. A semi-conductor diode cannot be used as a/an
*Detector *Amplifier *Oscillator *Switch
5. A PN-junction diode conducts when it is
*Forward biased *Reverse biased *Zero biased
*none of these
6. The word transistor means
*Transfer resistor
*Transfer conductor
*both a&b *none of these
7. Transistor is ______ terminal device.
*1
*2
*3
*5
8. A diode is ________ terminal device.
*1
*2
*3
*5
9. FM & AM are the applications of
*Rectification
*Oscillation
*Modulation
*Amplification
10.The application of the electrical potential across the semiconductor is called
*Oscillation
*Switching
*Biasing
*All of these
11.There are _______ types of biasing.
*2
*4
*6
*8
12.If P type substance is connected with +ve terminal and N type substance is connected with –
ve terminal then it is called _________ biasing
*Forward
*Reverse
*Reciprocal
*Multiple
13.If P type substance is connected with -ve terminal and N type substance is connected with
+ve terminal then it is called _________ biasing
*Forward
*Reverse
*Reciprocal
*Multiple
14.In N-type semiconductor, majority charge carriers are:
*Holes
*Electron *Positron *Neutron
15.In P-type semiconductor, majority charge carriers are:
*Holes
*Electron *Positron *Proton
16.In N-type semiconductor, minority charge carriers are:
*Holes
*Electron *Positron *Neutron.
17.P-type semi-conductor is obtained by adding impurity materials of group
*5th elements
*3rd elements
*4th elements
*6th elements
18.The forbidden energy gap between the valence band & the conduction band in a semiconductor is:[2010]
*wide
*narrow
*zero
*infinite
19.The forbidden energy gap between the valence band & the conduction band in a semiconductor is:[2002]
*Fairly large
*relatively narrow
*zero
*infinite
20.The speed of electromagnetic waves depends on:[2002]
*permeability
*permittivity
*both a&b *none of these
21.The elements of group IV-A like Ge& Si can be converted to N-type semi-conductor by
*adding impurity of group V elements
*adding impurity of group III elements
*adding impurity of both group V & III elements
*none of the above
22.The elements of group IV like Ge& Si can be converted to P-type semi-conductor by:[2003]
*adding impurity of group V elements
*adding impurity of group III elements
*adding impurity of both group V & III elements
*none of the above
23.Donor impurities are:[2010]
*Ge& Si
*In &Ga
*Sb& As *Li &Ga
24.Emitter base junction is forward biased in:[2011]
*PNP transistor *NPN transistor *Rectifier *none of these
25.Pn-junction Diode works as an insulator if connected:[2011]
*in Forward bias
*in Reverse bias
*to A.C source
*all of these
26.With the increase of temperature the resistance of a semi-conductor:[2012]
*increases *decreases *remains constant *becomes zero
27.The speed of electromagnetic waves is given by:[2013]
*√
𝝁
𝟏
𝒐 𝜺𝟎
*
1
𝜇𝑜 𝜀0
*√𝜇𝑜 𝜀0
*𝜇𝑜 𝜀0
28.The diode which gives visible light when energized is called:[2013]
*LCD
*photo-diode
*LED
*photo voltaic diode
29.Holes in a semi-conductor is actually the:[2014]
*electron *positron *helium nucleus *vacancy in valance band
30.In P-type semiconductor, minority charge carriers are:
*Holes
*Electron *Positron *Proton.
PAST PAPER QUESTIONS
1. What is semiconductor diode? How is it used for half wave and full wave rectification?(2012,
2005)
2. Explain the formation of potential barrier in PN junction. (2011)
3. What is PN junction? Explain the formation of potential barrier in PN junction.(2010)
4. Describe the working of PNP or NPN transistor. (2009, 2006, 2003)
5. Differentiate between Intrinsic and Extrinsic semiconductors. With the help of diagram
explain the working of a full wave rectifier.(2008)
6. How are P-type & N-type semiconductors made? Explain with the help of a diagram the
forward and reverse biasing of PN junction. (2007, 2002)
7. Calculate the speed of electromagnetic wave.(2008)
8. What is a diode? How is it used as a rectifier?(2003)
9. What is doping? How are P-type & N-type semiconductors made? (2002)
ADVENT OF MODERN PHYSICS
Multiple choice Questions
1. Theory of relativity was put forward by
* Newton * De-Broglie
* Heisenberg
* Einstein
2. Einstein was awarded a Nobel prize for his work on
* Theory of relativity
* Photoelectric effect
* Quantum theory
* All of these
3. De –Broglie wave length is:[2014,2011]
Chapter#17
* λ = h/mv * h = λ /mv
* λ = m/he
* λ = v/mh
4. Wave particle duality concept can be understood with the help of following equation:
* λ = h/mv * h = λ /mv
* λ = m/hv
* λ = v/mh
5. The absorption of the incident radiation by a black body is[2002]
*0%
* 50 %
* 100 %
* 90 %
6. The process in which a photon disintegrates into positron-electron pair is called: [2004]
* Pair Annihilation
* Fission * Dispersion
* pair production
7. The process in which a positron-electron pair is combined to produce photon is called:
* Pair Annihilation
* Fission * Dispersion
* pair production
8. Another name of pair production is
* Materialization
* Radioactivity * Spectrum
* All of these
9. The process in which Ultraviolet radiation falls on metallic surface to eject electron out of it
is:
* Compton’s effect
* Photoelectric effect
* Resistivity
* All of above
10.Which of the following confirms particle nature of light?
* Interference
* Photoelectric effect * Black body radiations
11.Which of the following wave nature of light?
* Compton’s effect
* Photoelectric effect
* Black body radiations
* All of the above
12.Which of the following confirms dual nature of light?
* Compton’s effect
* Photoelectric effect
* Black body radiations
* De-Broglie’s Hypothesis
13.According to Wien’s law, radiations of maximum wavelength come out of a black body is
inversely proportional to :
* Absolute temperature
* Fourth power of temperature
* Cube of temperature
* Square of temperature.
14.The mathematical expression 𝜆𝑚𝑎𝑥 × 𝑇 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 is called:[2014, 2012]
*Stefan’s law
*Rayleigh jeans law
*Wien’s displacement law
*Plank’s law
15.The energy radiated per second per unit area from the surface of a black body is directly
proportional to its absolute temperature raised to power:[2014]
*One
*two
*three
*four
16.This was the first experimental verification of Einstein’s mass-energy relation :[2013]
*deuteron induced reaction
*protons induced reaction
*Gama induced reaction
*none of these
17.According to Einstein’s special theory of relativity, the mass of a particle moving with
speed of light will become:[2012]
*zero
*double
*infinite
*ten times
18.According to Stefan-Boltzmann’s law, Energy of maximum intensity come out of a black
body is directly proportional to :
* Absolute temperature
* Fourth power of temperature
* Cube of temperature
* Square of temperature.
19.According to Rayleigh-Jean’s law, Energy of maximum intensity come out of a black body
is inversely proportional to :
* Wavelength
* Fourth power of wavelength
* Cube of wavelength
* Square of wavelength.
20.In photoelectric effect, the number of electrons ejected out of the surface of metallic surface
depends on:
* Energy of incident light
* Intensity of incident light
* Color of incident light
* none
21.In order to increase the kinetic energy of an ejected photo electrons, there should be an
increase in:[2011]
*frequency of radiation
*wave length of radiation
*intensity of radiation
*both wavelength & intensity
22.As the temperature of black body is raised, the wavelength corresponding to the maximum
intensity shifts towards:[2011]
*shorter wavelength
*longer wavelength
*similar wavelength
*lower frequency
23.Einstein’s photoelectric equation is:[1996,2002]
1
1
* 𝑚𝑣 2 = ℎ𝑣 + ∅
*ℎ𝑣 = 𝑚𝑣 2 − ∅
2
𝟏
2
𝟐
*𝒉𝒗 = ∅ + 𝒎𝒗
*none of these
𝟐
24.When fast moving electrons are stopped by a metal of high atomic weight, the phenomenon
gives rise to:[1997,2002]
*X-rays
*β-rays
*γ-rays
*α-rays
25.Einstein’s theory of relativity states that the speed of light in vacuum is:[1999]
*independent of the motion of the source & observer
*affected by the ether drift
*dependent of the motion of the source & observer
*all of these
26.Number of photo electrons emitted from a metal depends upon:[2000, 2004]
*frequency of incident light
*wavelength of incident light
*intensity of incident light
*all of these
27.The relativistic changes in mass, length & time in daily life are not observed because
*the masses of objects are very large
*the sizes of objects are very large
*the velocity of objects is very small in comparison to the velocity of light
*none of the above[2001]
28.In Compton effect, the scattered photon has:[2001]
*greater frequency & smaller wave length
*smaller frequency & greater wave length
*greater frequency & greater wave length
*none of these
29.The maximum kinetic energy of photo electrons emitted from a metal depends upon
*the frequency of incident light only:
*the wave length of incident light only
*the work function of the metal only
*all of them[2002]
30.Max plank is well known for from the given options[2002]
*energy quantization
*energy conservation
*wave particle duality *momentum quantization
31.A frame of reference is called inertial if it is [2002]
*rotatory *accelerated
*moving with a uniform velocity
*vibratory
32.According to uncertainty principle:[2002,2012]
*(∆𝑥)(∆𝑡) ≈ ℎ
*(∆𝒙)(∆𝒑) ≈ 𝒉 *(∆𝐸)(∆𝑡) ≈ ℎ *(∆𝑥)(∆𝐸) ≈ ℎ
33.Pair production is only possible when incident photon has the wave length of the order of
:[2012]
-4
*10 m
*10-6m
*10-10m
*10-14m
34.The frequency of incident radiation corresponding to the work function is called:[2005]
*fundamental frequency
*working frequency
*critical frequency
*threshold frequency
35.The radiation from a black body depends upon the:[2005]
*material of the body
*size of the body
*shape of the body
*temperature of the body
36.As a result of elastic collision between a photon & an electron the
*frequency of photon increased
*wave length of photon increased
*energy of photon increased
*X-rays are produced
37.The emissive power of a black body is proportional to:[2010]
*T
*T5
*T-4
*T4
38.The phenomenon of pair production takes place if the energy of photon is greater
than:[2010,2014,2011]
*1.0Mev
*1.02Mev *0.051Mev *none of these
39.The frequency at which photoelectric effect takes place is called:
* Alternating frequency
* Oscillating frequency
* Threshold frequency
* Capacitive frequency
Long Questions
1. What is the photoelectric effect? Discuss the results with the help of graph and derive
Einstein’s photoelectric equation. (2008, 2011, 2006,2003)
2. What is Compton’s effect? Explain it on the basis of Quantum theory. Derive the
relation
for the Compton’s Shift. (2007,2009, 2004, 2003)
3. What are Black Body and Black Body Radiation? State the laws governing Black body
Radiation. Give their mathematical expression.
(2007)
4. What are the postulates of special theory of relativity? Discuss briefly the results of Einstein’s
theory of relativity. (2006, 2002)
Short Questions
5. Explain the process of pair production & annihilation of matter briefly.
(2009)
6. Derive momentum of photon?
Numerical from Past Papers
1. Find the cut off wave length for a given metal whose work function is 4.14eV. (1987,2001)
(Ans 3002.7 Ao)
2. The work function of a certain metal is 3.0eV. when this metal is illuminated by the infra-red
light of 1.2 × 1015 𝐻𝑧. Find the maximum kinetic energy of emitted photons. (1989)
(Ans 3.156 × 10−19 𝑗 or 1.9725 eV)
3. The work function of a certain metal is 2.0eV. When this metal is illuminated by the light of
wavelength 3000Ao. Find the maximum kinetic energy of emitted photons. (1994)
(Ans3.43 × 10−19 𝑗 or 2.144 eV)
4. A 50 meter trailer is moving with relativistic speed. It passes over a bridge of length 40
meter. To an observer at rest with respect to the bridge at one instant the trailer seems to
overlap the bridge i.e. the ends of the trailer seem to coincide with the ends of the bridge, find
the speed of the trailer? (1991)
(Ans 3c/5)
5. The work function of photoemisive surface is 4.00 eV. What will be the velocity of the fastest
photoelectrons emitted from it by an incident light of frequency3 × 1015 𝐻𝑧? (1992)
(Ans 1.722 × 106 𝑚/𝑠)
6. The range of the visible light is 4000Ao to 7000Ao. will photoelectrons be emitted by a copper
surface of work function 4.4 eV, when illuminated by visible light? Give mathematical proof
of your answer. (1998)
(Ans 2825.3Ao)
7. Compare the energy of a photon of wavelength 2.6 × 10−6 𝑚 with the energy of X-ray
photon of wavelength2 × 10−10 𝑚.
8. What will be the relativistic velocity and momentum of a particle whose rest mass is mo and
the kinetic energy is equal to twice of its rest mass energy. (2011)
9. If the electron beam in TV picture tube is accelerated by 10000V, what will be the DeBroglie’s wavelength?
(2010,2005)
10. A sodium surface is shined with the light of wavelength 3 X 10 -7m. If the work function of
the sodium metal is 2.46e.V, find K.E of the photo-electrons and also the cut-off wavelength.
(2009, 2003)
11. Calculate the relativistic speed at which the mass of a particle becomes double its rest mass.
(2008)
12. In Compton’s scattering process, the fractional change in wavelength of X-rays is 1% at an
angle 120o, find the wave length of X-rays used in this experiment.
(2007)
-10
13. An electron exists within the region of 10 m, find its momentum uncertainty and
approximate kinetic energy.(2006)
14. What do you understand by the frame of reference and inertial frame of reference? Give one
example of each from daily life. Briefly discuss the three basic equations from relativity
predicting the relativistic changes.(2005)
15. Estimate the relativistic mass and wave length associated with an electron moving at 0.9C.
(2004)
16. Find the speed at which the mass of the particle will be doubled. (2002)
17. Given moC2 = 0.511 Mev. Find the the total energy E and kinetic energy K of an electron
moving with a speed of 0.85C.
(2002)
ATOMIC SPECTRA
Chapter#18
Multiple choice Questions
1. The wave length of x-ray is in the range.
*0.1nm to 1nm
*100 A0 to 1 A0
*0.1 A0 to 1m
*0.001nm to 1nm.
2. Hydrogen spectrum consists of lines in:[2008]
*Ultraviolet
*Visible
*Infra-red *All of the above.
3. Meta-stable states have the mean life of the order of:[2014]
*108 sec
*10-8 sec
*103sec
*3x10-3 sec.
4. The procedure adopted to achieve population inversion is called
*Ionization potential
*Excitation potential
*Optical pumping
*Stimulated emission.
5. The Ionization energy of an electron is
*14.7
*-13.6
*17.6
*zero
6. The situation in which the number of atoms in the higher energy level is greater than the
lower energy level is called
*Amplification
*deceleration
*Population inversion *Optical pumping
7. The radius of 1st orbit of hydrogen atom is
*2.12 A0
*0.92 A0
*0.53 A0
*None of these.
8. X-rays are:
*Stream of negatively charged Particles
*Electromagnetic waves
*Stream of Positively charged Particles
*none of these.
9. The Paschen series is obtained when an electron in hydrogen atom jumps from higher orbit
'n' is equal to
*2
*3
*4
*None of these.
10.x-rays are not deflected by
*Electric field
*Magnetic field *both of these
*none of these.
11.Ruby is a crystal of
*With impurity of Cl ions
*with the impurity of Cr ions
*Nacl with impurity of CA ions *none of these
12.The name of scientists who accidentally invented X-rays is:
*Faraday *Newton *Roentgen *None of these.
13.The laser is a device which we can produce
[2001]
*an intense beam of light
*a coherent beam of light
*a monochromatic beam of light
*all of above
14.Balmer series is obtained when all the transitions of electrons terminate on:[2001]
*3rd Orbit *4th Orbit *2nd Orbit *1st Orbit
15.Laser produces:[2012]
*an electron beam
*a neutron beam
*a coherent beam of light
*all of these
rd
16.When an electron falls from the 3 orbits to the 1st orbit in the Hydrogen atom, the lines
spectrum obtained belongs to:[2013]
*bracket series
*Lyman series
*blamer series
*paschen series
17.The frequencies in spectral lines emitted in Lyman series are in the _________ region[2006]
*visible
*infrared *X-rays
*ultraviolet
18.Bracket series of hydrogen atom spectrum lies in:[2010]
*Ultraviolet
*Visible
*Infra-red *All of the above.
19.Characteristics of Laser beam is
*Highly Intense
*Monochromatic
*coherent *All of these.
PAST PAPER QUESTIONS
1. State the basic postulates of Bohr’s theory of atomic structure. Derive the expression for the
radius of nth orbit of a Hydrogen atom. (2009, 2010, 2006, 2003, 2002)
2. What is LASER? Discuss the Meta stable state and population inversion in a lasing
material.(2008)
3. State the basic postulates of Bohr’s theory of atomic structure. Derive the expression for the
radius and energy of nth orbit of a Hydrogen atom. (2007)
4. Derive the expression for the radius and energy of nth orbit of a Hydrogen atom and the
equation of wavelength of the photons emitted in a Hydrogen atom.
(2005)
5. Describe the construction and working of Ruby Laser. (2003)
6. Why does Hydrogen spectrum contain a large number of spectral lines although it has only
one electron?(2011)
7. Differentiate between the principle of production of Laser and light from an incandescent
bulb. Also give their characteristics. (2010)
Numericals from Past Papers
1. Find the shortest wavelength radiation emitted in the Balmer series. Determine its energy in
e.V:(2010)
2. Calculate the longest and shortest wavelength radiation emitted in the Balmer series. (2008)
3. What minimum energy is required in an X- ray tube in order to produce X-rays with a
wavelength of 0.1 X -10 m.(2004)
4. Compare the energy of photon of wavelength 2 X 10-6 m with the energy of photon of
wavelength 2 X 10 -10 m (2004)
5. An electron in the Hydrogen atom makes transition from n = 2 energy state to ground state,
Find the wavelength in the ultraviolet region.(2003)
6. What is the longest wavelength of light capable of ionizing a Hydrogen atom? What energy
in electron volt is needed to ionize it?(2002)
7. A photon of 12.1 ev absorbed by a hydrogen atom originally in the ground state, raises the
atom to an excited state. What is the quantum number of this state?(2002)
NUCLEAR STRUCTURE
Chapter#19
Multiple choice Questions
1. The spontaneous emissions of radiations from heavy nucleus is called
*Nuclear Fission
*Nuclear Fusion
*Radioactivity
*None of these
2. The rod which is used to absorb neutron is called
*Reflectors
*control rods
*Moderators
*none of these.
3. Alpha particles are
*Protons
*Electrons
*negatively charged particles *Positrons.
4. The time in which half of the atom of the parent is decay into daughter element is called:
*Binding energy
*Mass defect
*Half-life *Decay constant.
5. Number of nuclei disintegrates per second is called
*Radioactivity
*Half-life
*Activity *none of these.
6. Good moderators have
*Low atomic number and large slowing down
*High atomic number and low slowing down power
*Low atomic number and low slowing down power
*None of these.
7. A breeder reactor does not require
*Reflector
*Core
*Coolants
*Moderators.
8. The binding energy per nucleon is called
*Potential energy
*Packing Fraction
*Kinetic energy
*All of these.
9. The energy released by the sun due to the process of
*Nuclear fission
*Nuclear fusion
*Nuclear radiation
*none of these.
10.Nuclear fusion is the source of energy in
*Nuclear reactor and sun
*Sun and Hydrogen bomb
*Nuclear reactor and atomic bomb
*Sun and atomic bomb.
11.The energy released when nucleons bound together to form a nucleus is called
*Atomic energy
*Kinetic energy
*Potential energy
*Binding
energy
12.The process of splitting a heavy nucleus into fragments is called
*Fission reaction *Nuclear fusion reaction
*nuclear reaction
*chemical reaction
13.The energy equivalent to the mass reduced in the formation of a nucleus is called:[2005]
*nuclear energy
*binding energy
*Potential energy
*fusion energy
14.The atomic number of an element is increased as a result of:[2005]
*α-radiation
*β-radiation
*pair production
*γ-radiation
15.In treating localized cancerous tumor, we use a narrow beam of :[2006]
*α-rays cobalt 60
*β-rays cobalt 60
*γ-rays cobalt 60
*laser cobalt 60
16.When nucleus emits an alpha particle its atomic number decreases by
*2
*1
*4
*3
PAST PAPER QUESTIONS
1. Define radioactivity. Explain the law of radioactive decay. Write the equations showing the
change in the parent nuclei by α, β and γ decay. (2011, 2006, 2004, 2003, 2002)
2. What is the Half-life of radioactive nuclei? State the law of decay and give relation b/w the
decay constant and the half-life. (2009, 2003)
3. What is nuclear Fission? Discuss Fission chain reaction. How are moderators used to control
fission in nuclear reactors? (2008,2011, 2002)
4. Do α, β and γ-rays come from the same element. Why do we find all three in many
radioactive elements?(2010)
Numerical:
1. A deuteron is formed when a proton & a neutron combine. Calculate the mass defect and
binding energy in MeV.
(2010)
2. If the number of atoms per gram of Radium is 2.666 X 1021 and it decays with a half-life of
1622 years. Find the decay constant and the activity of the sample.(2009)
3. Calculate the binding energy of a Hydrogen atom, when all the constant values are
known.(2007)
4. The half-period of 104Po210 is 140 days. By what percent its activity decreases per
week?(2006)
5.
6.
With the help of nuclear process prove that a neutron can disintegrate into proton and
electron. Write down the conservations equation in support of your answer.(2005)
Define the terms (i) Isotopes (ii) Binding energy (iii) Mass defect. (2004)
NUCLEAR RADIATION
Chapter#20
Multiple choice Questions
1. Geiger counter is a device to detect:
*Mass
*Momentum
*Charge
*Radiation
2. Solid state detectors work when they are:
*Forward biased
*Reverse bias
*not biased *none of these.
3. Normally G.M counter uses potential difference of:
*10 volt
*100 volt *1000volt *5000volt
4. The thin wire at the cathode of G.M tube acts as:
*Cathode *Anode
*Neutral
*None of these.
5. Geiger counter uses:
*Alcohol only
*Bromine *Argon
*Argon and Alcohol.
6. The track formed in the Wilson cloud chamber due to gamma rays is:
*Thin and broken line
*Thick continuous line
*Thick line track in random direction
*Whole region exposed to radiations.
7. The track formed in the Wilson cloud chamber due to Beta particles is
*Thin and broken line
*Thick continuous line
*Thick line track in random direction *Whole region exposed to radiations.
PAST PAPER QUESTIONS
Explain why the photograph of the alpha particle is thick and made of continuous line where as
that of Beta particles is
thin and made up of broken lines in the Wilson’s cloud
chamber?(2012)
In how many ways can gamma rays produce ionization of an atom? (2011)
Describe the principle, construction and working of a Wilson’s cloud chamber.(2010, 2008,
2006, 2003)
Describe the construction and working of a Geiger counter.(2007, 2004, 2002)