Download question bank physics class 10

ELECTICITY
1.
A student performs an experiment to study the magnetic effect of current around a
current carrying straight conductor. He reports that (i) for a given battery, the degree of
deflection of a N – pole decreases when the compass is kept at a point farther away from the
conductor. (ii) the direction of deflection of the north pole of a compass needle kept at a given
point near the conductor remains unaffected even when the terminals of the same battery
sending current in the wire are inter changed.
Which of the above observations of the student appears to be wrong and why?
2.
A household uses the following electric appliances:
(i)
Refrigerator of rating 400 W for ten hours each day.
(ii)
Two electric fans of rating 80 W each for twelve hours each day.
(iii)
Six electric tubes of rating 18 W each for 6 hours each day.
Calculate the electricity bill of the household for the month of June if the cost per unit of electric energy
is Rs. 3.00.
5 marks Questions
1. In a household electric circuit different appliances are connected in parallel to one another. Give two
reasons.
An electrician puts a fuse of rating 15A in that part of domestic electrical circuit in which an electrical
heater of rating 1.5kW, 220V is operating. What is likely to happen in this case and why? What change, if
any, needs to be made? (5)
2 (a) The electric power consumed by a device may be calculated by using either of the two expressions
P = 12R or P =V2/R. The first expression indicates that it is
Directly proportional to R whereas the second expression indicates inverse proportionality. How can the
seemingly different dependence of P on R in these expressions be explained?
(b) (i) A 100 W electric bulb is connected to 220 V mains power supply. Calculate the strength of the
electric current passing through the bulb. (ii) If the same bulb is taken to U.S.A where the main power
supply is 110 V, how much electric current will pass through the bulb when connected to mains?
3) State and explain Ohm’s law
5. Define Resistance and its S.I.Unit? How the current will change when the resistance is doubled :6) On what factors resistance of a conductor depends? Give the order of resistivity of conductors
and insulators.
7. Derive the equation for resultant resistance of Resistors in series &parallel
8. Derive the equation for resultant resistance of Resistors in parallel
MAGNETIC EFFECTS OF ELECTRIC CURRENT
Q.1 A straight wire carrying electric current is moving out of plane of paper and is perpendicular
to it. What is the direction and type of induced magnetic field lines?
1. On what effect of an electric current does an electromagnet work?
2. What is the frequency of AC (Alternating Current) in India?
3. On what effect of an electric current does a fuse work?
Q.2 How can it be shown that magnetic field exist around a wire carrying current?
How can a solenoid be used to magnetise a steel bar.
Q.4 Why can’t two magnetic field lines ever intersect?
Q.5 Can a 5 A fuse be used in wire carrying 15 A current? Why?
Q.6 Give the factors that affect strength of magnetic field at a point due to a straight
conductor carrying current.
Q.7 Where do we connect a fuse: with live wire or with neutral wire?
Q.8 Give two uses of electromagnets.
Q.9 Name any two devices which use permanent magnets.
Q.10 Draw the magnetic field lines representing uniform magnetic field.
Q.11 A current-carrying straight conductor is placed in the east-west direction. What will be
the direction of the force experienced by this conductor due to earth’s magnetic field? How
will this force get affected on? (a) reversing the direction of flow of current (b) doubling the
magnitude of current
Q.12 An electron enters a magnetic field at right angles to it as shown in fig. The direction
of the force acting on the electron will be:
to the right (b) to the left (c) out of the page (d) into the page
Q.13 Why is the earth pin thicker and longer than the live and the neutral pins?
Q.14 A coil of insulated copper wire is connected to a galvanometer. What would happen if a
bar magnet is (i) Pushed into the coil?
(ii)
Withdrawn from inside the coil?
(iii)
Held stationary inside the coil?
1. Why does a current carrying conductor kept in a magnetic field experience force? On
what factors does the direction of this force depend?
Name and state the rule used for determination of direction of this force.
2.Explain a) Electric fuse b) Overloading c) Short circui
3. Explain Direct and Alternating current
4. Draw the pattern of magnetic field lines of a current carrying solenoid. What does the
pattern of fieldlines inside the solenoid indicate? Write one application of magnetic
field of current carrying solenoid.
5 marks Questions & Magnetic Effects of Electric Currents
1. Explain with an experiment principle of Electromagnetic induction? Which law will
gives the direction of electric current?
2.Explain Domestic electric circuit?
3.Explain the meaning of the word ‘electromagnetic’ and ‘induction’ in the term
electromagnetic induction. On what factors does the value of induced current produced
in a circuit depend? Name and state the rule used for determination of direction of
induced current. State one practical application of this phenomenon in every day life.
HOTS
Q1.On what factors does the magnetic field intensity at the centre of the circular coil
carrying depend?
Q2.State the principle used to determine the force experienced by a conductor carrying
current in uniform magnetic field ?
Q3.On what factors does the force experienced by a conductor carrying current in
uniform magnetic field depend? A3.Force experienced by a conductor depends on
Q4.On what factors does the strength of a magnetic field at a point due to a straight
conductor carrying current depend ?
Q5.Differentiate between direct current and alternating current.
Q6.A switch is always connected in
(a)earth wire
(b)neutral wire
(c)live wire
Q7.What type of connection is used in household circuits?
Q8.State the principle of the working of an electric motor.
Q9.State the principle of a D.C generator.
Q10.State the characteristics of magnetic field lines.
Q11.State Right Hand Thumb Rule.
Q12.Define the phenomenon overloading.
Q.13. How can it be shown that magnetic field exist around a wire carrying current?
Q.14 Will be the direction of the force experienced by this conductor due to earth’s
magnetic field? How will this force get affected on? (a) reversing the direction of flow of
current (b) doubling the magnitude of current.
The direction of earth’s magnetic field is from G-south to G-north.
Q.15. A wire carrying current passes through the middle of the plane A perpendicular to
it. If a magnetic needle is placed in th
thee plane parallel to the wire. What will be the
direction of the needle?
Q.16.A wire carrying current passes through the middle of the plane A perpendicular to
it. If a magnetic needle is placed in the plane perpendicular to the plane A, what will be
the direction of the needle?
Q.17.If a magnetic needle is placed at the north pole in a horizontal plane, in what
direction it will indicate? Why?
Q.18.If a magnetic needle is placed at the north pole in a vertical plane, what will be its
direction?
Q.19. Is a circular coil carrying current similar to magnet?
Q.20. What is the role of soft iron in the core of a solenoid?
SOURCES OF ENERGY
SHORT QUESTIONS WITH ANSWERS (2 MARKS)
Q.1.
What is solar cell ? Name two materials mostly used for making
solar cells.
Q.2.
What type of mixture are separated by fractional distillation?
Name the fraction of crude oil whose boiling point is more than 350oC. Where
is it mostly used as a fuel?
3.How were fossil fuels formed ? How these fossils fuels were made
Q.4. Define the term ‘fuel’. What are primary and secondary fuels? To which class of
fuel do the following belong: Coke , Wood, Petroleum, LPG.
Q.5. 48 kJ of energy is produced per minute in a nuclear reactor. Calculate the number
of fissions which would be taking place in the reactor per second, if the energy released
per fission is 3.2 x 10 -11 J.
Give one example of a nuclear fusion reaction. Describe one method ffor
or making such reactions
possible
Q.6. Which type of nuclear process is currently used in nuclear electricity generators?
Give one example each for the substances used in this context as (i) coolants (ii)
moderators and (iii) nuclear fuel?
Q.8.For producing electricity,
ectricity, the energy from flowing water is preferred to energy obtained by
burning coke. State two reasons for it
Q.9. Define a nuclear fusion reaction .Describe the conditions for the occurrence of a nuclear
fusion reaction.
H + 2H1
21
3
He2 +1no
Q.10. Name the places of out country where fields of natural gas are found. Why is it called a
clean fuel? Give two reasons.
Q.11. What is the cause of release of unusually large energies in nuclear fission reactions?
How is the energy per fission calculated?
Q.12. The use of dry wood as domestic fuel is not considered as good. State
two reasons for it.
Q.13.In one fission of uranium, 3x10-11J of energy is made available. Calculate the total number
of fissions necessary per second to generate power of 15 kW
Q.14.How is charcoal obtained from wood? Why is charcoal considered better
fuel than wood?
Q.15.Describe how hydroenergy can be converted into electrical energy.
Write any two limitations by hydroenergy.
Q16.what is geothermal energy? What are its advantages?
SHORT QUESTIONS WITH ANSWERS (3 MARKS)
Q.1. How many groups of nuclei are generated in the fission of 235 U? what are their
characteristics? Explain briefly the terms (i) prompt (ii) delayed, and (iii) spontaneous
fission.
Q.2. Write the four processes that can take place, after neutrons are emitted in a fission reaction.
Which of these processes will cause the fission to continue? How is the energy of released
neutrons lowered from 2MeV to 0.025MeV?
. Q.3. (i) Write the value of solar constant of sun.
(ii) what type of mirror is used in Box Type Solar cooker?
(iii)why it is difficult to use hydrogen as a source of energy?
(iv)what is the maximum temperature attained in a concave reflector type
solar cooker?
(v)Fossil fuels are classified as non-renewable source of energy. Explain
why.
. Q.4. (a) Why is solar cooker box covered with a plane glass plate?
(b) Why is the energy of water flowing in a river considered to be an indirect
form of solar energy?
(c) Write one advantage of nuclear fission reaction
Q.5. (a) State one limitation of solar energy available from solar cells.
(b) What is the minimum wind velocity
required to obtain useful energy with a
wind will ? (c) Define the term ‘nuclear
fission’.
HOTS
Q.1. Name two gases, other than carbon-dioxide that are given out during burning of fossil
fuels and contribute towards acid rain formation?
Q.2. Why are many thermal power plants set up near coal or oil fields?
. Q.3. Justify in one sentence that hydropower (hydel electricity) is a renewable source of
energy.
Q.4. Out of two solar cookers, one was covered by a plane glass slab and the other was left
open. Which of the two solar cookers will be more efficient and why?
Q.5. A student constructed a box type solar cooker. He found that it did not work efficiently.
What could this be due to? Give any four possible mistakes in the construction and operation of
the cooker. What maximum temperature can ordinarily be reached inside a solar cooker?
Q.6. A student has set up a solar cooker in a box by using a black painted aluminum sheet, a
black cooking vessel, some glass wool, a glass sheet and a mirror plate. What is the role of
each item used in the solar cooker?
Q.7. Solar energy can be harnessed directly as well as indirectly. Give two
examples of each type.
Q.8. What is anaerobic degradation
Q.9. what is a solar power plant? Name one such plant in our Country.
Q.10. How can wood be made a renewable source of energy ?
Q.11. What causes the wind to blow?
Q.12.To which category of fuel does hydrogen belongs to?
Q.13. Why is Nuclear fuel classified as renewable source of energy?
Q.14. Why the Geothermal energy is classified as a renewable sources of energy?