Download Unit – IV - India Study Channel

Akshara International School
Ashok Nagar, Vijayawada – 07
Question Bank
Light:
01. Define focal length and radius of curvature for a spherical mirror and give the
relation between them.
02. What are real and virtual images?
03. What is a spherical mirror? Distinguish between a concave mirror and a convex
mirror.
04. Define the principal focus of a concave mirror. Out of convex mirror and concave
mirror, whose focus is situated behind the mirror?
05. Where should an object be placed in front of the concave mirror so as to obtain its
magnified erect image?
06. What is the angle of incidence, when a ray of light falls on the spherical mirror
from the centre of curvature? Can we obtain the image of an object formed by
convex mirror on a screen? If not, why?
07. How can one ascertain without touching, whether a given mirror is plane, convex
or concave?
08. An object is placed in front of a concave mirror between its focus and centre of
curvature. Show with the help of a ray diagram, the position, size and nature of
the image formed.
09. If an object is placed at a distance of 8 cm from a concave mirror of focal length
10 cm, discuss the nature of the image formed by drawing the ray diagram.
10. Give at least three uses of a concave mirror.
X (CBSE)
Question Bank (Physical Science)
Page 1 of 18
11. An object 2.5 cm tall is placed at a distance of 15cm from a concave mirror of
focal length 10 cm. By means of an accurate ray-diagram, determine the position,
size and nature of the image formed.
12. Write the sign convention used in optics.
13. Which type of mirror has: (i) positive focal length? (ii) negative focal length?
14. All the distances are measured from the ________of a spherical mirror.
15. At what distance from a concave mirror of focal length 10 cm should an object be
placed, so that its image is formed 20 cm from the mirror?
16. If the magnification of a body of size 1m is 2, what is the size of the image?
17. State the relation between object distance, image distance and focal length of a
mirror.
18. What is the ratio of the height of an image to the height of the object known as?
19. Define linear magnification produced by a mirror.
20. Which mirror has a wider field of view?
21. Which type of mirror is used in vehicles to see the traffic on the rear side?
22. Why does a driver prefer to use a convex mirror as a back view mirror in an
automobile?
23. Draw a ray diagram to show the formation of image in a convex mirror. What
happens to the image when the object is moved away from the mirror?
24. An arrow 2.5 cm high is placed at a distance of 25 cm from a diverging mirror of
focal length 20 cm. Find the nature, position and size of the image formed.
25. What is refraction?
26. What are the laws of refraction?
27. Can absolute refractive index of a medium be less than unity?
28. Can relative refractive index of a medium w.r.t. another be less than unity?
29. Define the terms ‘critical angle’ and ‘total internal reflection’.
30. What type of lens is an air bubble inside water?
31. What are the uses of putting two lenses in contact with each other?
32. Define refractive index of a material. Distinguish between the terms absolute and
relative refractive index of a medium. How are they related?
X (CBSE)
Question Bank (Physical Science)
Page 2 of 18
33. Give an expression for refractive index in terms of velocities of light.
34. Refractive index of glass is 1.5. Find the speed of light in glass, if its speed in air
is 3x108ms-1.
35. What is a lens? Distinguish between a convex and a concave lens?
36. A point inside the lens through which the light passes undeviated is called __.
37. Which of the two is a diverging lens: convex or concave?
38. State whether a concave lens has a virtual focus or real focus.
39. Draw a ray diagram to show the formation of a real magnified image by a convex
lens.
40. Where should an object be placed in order to use a convex lens as a magnifying
glass?
41. For what position of an object, a real, diminished image is formed by a convex
lens?
42. In which physical quantity is the power of a lens measured?
43. The focal length of a convex lens is 25 cm. What is its power?
44. The power of a lens is -2D. What is its focal length?
45. What do you understand by the power of a lens? Define its unit.
46. State the Cartesian sign convention for lenses.
47. How is power of a lens related to focal length?
48. Which type of lens has a (i) negative power? And (ii) positive power?
49. What is the difference between the mirror formula and the lens formula?
50. A convex lens produces an inverted image magnified three times of an object
placed at a distance of 15 cm from it. Calculate (i) focal length of the lens and (ii)
power of the lens.
51. An object 4 cm high is placed at a distance of 10cm from a convex lens of focal
length 20 cm. Find the position, nature and size of the image.
52. Show by drawing a ray-diagram that the image of an object formed by a concave
lens is virtual, erect and diminished.
53. If the image formed by a lens is always diminished and erect, what is the nature of
the lens?
X (CBSE)
Question Bank (Physical Science)
Page 3 of 18
54. An object of height 4 cm is placed at a distance of 15 cm in front of a concave
lens of power -10 dioptres. Find the size of the image.
Questions From Previous Papers
55. Draw a ray diagram to show the i) Position and (ii) nature of the image formed
when an object is placed between focus F and pole P of a concave mirror.
56. A 5.0 cm tall object is placed perpendicular to the principal axis of a convex lens
of focal length 20 cm. The distance of the object from the lens is 30 cm. By
calculation determine (i) the position, and (ii) the size of the image formed.
57. A ray of light is incident on a concave mirror as shown below
Redraw the above diagram after completing
the path o
58. An object is placed at a distance of 12 cm in
front of a concave mirror. It forms a real image four times larger than the object.
Calculate the distance of the image from the mirror.
59. State the relation between object distance, image distance and focal length of a
spherical mirror. A concave mirror of focal length 15 cm forms an image of an
object kept at a distance of 10 cm from the mirror. Find the position, nature and
size of the image formed by it.
60. Draw a labeled ray diagram to locate the image of an object formed by a convex
lens of focal length 20 cm when the object is placed 30 cm away from the lens.
61. During its passage from one medium to another, when does a light ray change its
path?
62. Define the term absolute refractive index of a medium?
63. With the help of a ray diagram explain the term ‘critical angle’.
64. For a ray of light going from a denser medium to air, what is the value of
refractive index of the medium if the critical angle is equal to 450.
65. Where will the image be formed by a concave mirror when an object is placed
between the pole and the focus point of the mirror?
X (CBSE)
Question Bank (Physical Science)
Page 4 of 18
66. With respect to air the refractive indices of water and benzene are 1.33 and 1.50
respectively. Calculate the refractive index of benzene with respect to water.
67. What are the values of (i) the angle of incidence, and (r) the angle of reflection for
normal incidence on a plane mirror surface?
68. Light enters from air into a glass plate which has a refractive index of 1.50.
Calculate the speed of light in glass. The speed of light in air is 3.0 x 10 8 ms-1.
69. A convex lens has a focal length of 25 cm. Calculate the distance of the object
from the lens if the image is to be formed on the opposite side of the lens at a
distance of 75 cm from the lens. What will be the nature of the image?
70. With the help of ray-diagrams show the phenomenon of total internal reflection of
light and the concept of critical angle for a transparent medium.
71. A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of
focal length 20 cm. The distance of the object from the lens is 30 cm. Find the (i)
position, (ii) nature and (iii) size of the image formed.
72. What is meant by ‘critical angle’ for a ray of light going from one medium into
another?
73. What is the consequence of making angle of incidence of light, at an interface,
greater than the critical angle?
74. Why does a cut diamond shine more than a glass piece with diamond cut?
75. What wilt be the focal length of a lens whose power is given as + 2.0 D?
76. An object 3 cm high is placed at a distance of 20 cm in front of a convex lens of
focal length 12 cm. Find the position, nature and size of the image formed.
77. An object 3 cm high is placed at a distance of 9 cm in front of a concave mirror of
focal length 18 cm. Find the position, nature and size of the image formed.
78. Find the position, nature and size of the image formed by a convex lens of focal
length 12 cm of an object 3 cm high placed at a distance 20 cm from it.
79. Find the position, nature and size of the image of an object 3 cm high placed at a
distance 9 cm from a concave mirror of focal length 18 cm.
80. If the magnification of a body of size 1m is 2, what is the size of the image?
X (CBSE)
Question Bank (Physical Science)
Page 5 of 18
ELECTRICITY
01. What do you understand by the term “potential difference”? What is the S.I. unit
for it?
02. By what name is the unit joule/coulomb called?
03. Name the instrument which is used to measure potential difference.
04. Define Volt.
05. Calculate the work done in moving a charge of 4 coulomb from a point at 220
volts to another point at 230 volt.
06. Define electric current. Give its unit.
07. Define Ampere.
08. How voltmeter and Ammeter are connected in a circuit?
09. What is a voltmeter and what is an ammeter?
10. If the charge on an electron is 1.6 x 10-19 C, how many electrons should pass
through a conductor in 1 second to constitute 1 ampere current?
11. What is Ohm’s law? Explain how it is used to define the unit of resistance.
12. Name the unit in which electrical resistance is measured.
13. What happens to the resistance as the conductor is made thinner?
14. Distinguish between conductors, resistors and insulators.
15. The potential difference between the terminals of an electric iron is 240V and the
current is 5 A. What is the resistance of the electric iron?
16. Keeping the potential difference constant, the resistance of a circuit is doubled.
By how much does the current change?
17. What are Ohmic and non-Ohmic conductors? What is the shape of the graph
drawn between current and voltage in the above cases?
18. With the help of a diagram, derive the formula for the equivalent resistance of
three resistances connected in series.
19. With the help of a diagram, derive the formula for the equivalent resistance of
three resistances connected in parallel.
20. Give the law of combination of resistances in series.
X (CBSE)
Question Bank (Physical Science)
Page 6 of 18
21. Give the law of combination of resistances in series.
22. If n resistances of R ohm each are connected in parallel, what will be their total
resistance?
23. If n resistances of R ohm each are connected in series, what will be their total
resistance?
24. Two resistances when connected in parallel give resultant value of 2 ohm; when
connected in series the value becomes 9 ohm. Calculate the value of each
resistance.
25. In order to get the resultant resistance greater than the greatest of the given
resistances how they will be connected?
26. In order to get the resultant resistance less than the least of the given resistances
how they will be connected?
27. Define electric power. Write its S.I. unit.
28. How many joules are equal to 1 watt-hour?
29. Name the commercial unit of energy.
30. Define kilowatt-hour. Calculate the cost of operating a heater of 500W for 20
hours at the rate of 35 paise per unit.
31. Which has a greater resistance, a 100 watt bulb or a 60 watt bulb?
32. State whether an electric heater will consume more electrical energy or less
energy per second when the length of its heating element is reduced. Give reasons
for your answer.
33. A bulb is rated as 250V; 0.4A. Find its : (i) power and (ii) resistance.
34. State three factors on which the heat produced by an electric current depends.
35. Give two applications of heating effect of electric current.
36. A resistance of 25 Ohm is connected to a 12 V battery. Calculate the heat energy
in joules generated per minute.
37. The current passing through a room heater has been halved. What will happen to
the heat produced by it?
38. Give two reasons why different electrical appliances in a domestic circuit are
connected in parallel.
X (CBSE)
Question Bank (Physical Science)
Page 7 of 18
39. What name is given to the device which automatically cuts off the electricity
supply during short circuiting in household wiring?
40. Of what substances is the fuse wire made? Why?
Questions from Previous Papers
41. What is the S.I. unit of electric potential ?
42. An electric iron has a rating of 750 W, 220 V. Calculate current passing through
it, and its resistance, when in use.
43. (a) What is meant by ‘Electric Resistance’ of a conductor ?
(b) A wire of length L and resistance R is stretched so that its length is doubled
and the area of cross-section is halved. How will its: resistance change?
resistivity change?
44. What is meant by the statement, “Potential difference between points A and B in
an electric field is 1 volt.” ?
45. An electric lamp is marked 100 W, 220 V. It is used for 5 hours daily. Calculate
its resistance while glowing. Energy consumed in kWh per day.
46. a) State Ohm’s Law.
b) Draw a schematic diagram of the circuit for studying Ohm’s Law.
47. An electric heater is used on 220 V supply and takes a current of 3.4 A. Calculate
(i) its power and (ii) its resistance, when it is in use.
48. (a) Draw a schematic diagram of a circuit consisting of a battery of five 2 V cells,
a 5 ohm resistor, a 10 ohm resistor and a 15 ohm resistor, and a plug key, all
connected in series.
(b) Calculate the electric current passing through the above circuit when the key is
closed.
49. Draw a diagram to show how two resistors R1 and R2 are connected in series.
50. In a circuit if the two resistors of 5 ohm and 10 ohm are connected in series, how
does the current passing through the two resistors compare?
51. A bulb is rated at 5.0 volt, 100m A. Calculate its power and resistance.
X (CBSE)
Question Bank (Physical Science)
Page 8 of 18
52.There are two electric bulbs, marked 60 W; 220 V and marked 100 W; 220 V.
Which one of the two has a higher resistance?
53. In a household 5 tube lights of 40 W each are used for 5 hours and an electric
press of 500 W for 4 hours every day. Calculate the total electrical energy
consumed by the tube lights and press in a month of 30 days.
54. Out of the two, a toaster of 1kW and an electric heater of 2 kW, which has a
greater resistance?
55. Name a metal which offers higher resistance to the passage of electricity than
copper.
56. Which has a higher resistance: a 50 W lamp bulb or a 25 W lamp bulb and how
many times?
57. A torch bulb is rated 2.5 V and 750 mA. Calculate (i) its power, (ii) its resistance
and
(iii)
the
energy
consumed
if
this
bulb
is
lighted
for
four hours.
58. A wire of resistance 10 ohm is bent in the form of a closed circle. What is the
effective resistance between the two points at the ends of any diameter of the
circle?
59. If a 24 V battery is connected to the arrangement of resistances given below,
Calculate the total effective resistance of the
circuit and the total current flowing in the circuit.
60. State the formula correlating the electric current
flowing in a conductor and the voltage applied across it. Also show this
relationship by drawing a diagram. What would be resistance of a conductor if the
current flowing through it is 0.35 ampere when the potential difference across it
1.4 volt?
61. An electric bulb draws a current of 0.2 A when the voltage is 220 volts. Calculate
the amount of electric charge flowing through it in one hour.
X (CBSE)
Question Bank (Physical Science)
Page 9 of 18
62.Three resistors are connected as shown in the figure. Through a resistor 5 ohm a
current of one ampere is flowing: (a) what is the p.d.
across
AB
and
across
AC?
(b) what is the current through the other two resistors?
(c) what is the total resistance?
63. A bulb is rated at 200 V-100 W. What is its resistance? Five such bulbs burn for
4 hours. What is the electrical energy consumed? Calculate the cost if the rate is
50 paise per unit.
CHEMICAL REACTIONS AND EQUATIONS
01. What is meant by a chemical reaction? Give an example.
02. State the characteristics of chemical reactions.
03. Why should magnesium ribbon be cleaned before burning in air?
04. What is a chemical equation? Explain with the help of an example.
05. What are balanced and unbalanced chemical equations? Give examples.
06. Why should chemical equations be balanced?
07. What do you understand by exothermic and endothermic reactions? Explain with
examples.
08. Aluminium burns in chlorine to form aluminium chloride, AlCl3. Write a balanced
equation for this reaction.
09. Carbonmonoxide reacts with hydrogen under certain conditions to form
methanol(CH3OH). Write a balanced chemical equation for this and state the
conditions under which this reaction takes place.
10. What do you understand by combination reaction, decomposition reaction? Give
examples.
11. What happens when silver chloride is exposed to sunlight? Write a chemical
equation for this reaction. Also give one use of such a reaction.
X (CBSE)
Question Bank (Physical Science)
Page 10 of 18
12. Why are decomposition reactions called the opposite of combination reactions?
Explain with equations of these reactions.
13. What is meant by a displacement reaction, double displacement reaction? Give
examples.
14. What do you mean by precipitation reaction? Give an example.
15. Why does the colour of copper sulphate solution change when an iron nail is kept
immersed in it?
16. Explain the following in terms of gain or loss of hydrogen with one example each:
(a) oxidation
(b) reduction
17. Explain the term ‘corrosion’ with an example.
18. Explain the term ‘rancidity’
19. What are anti-oxidants? Why are they added to fat and oil containing food?
20. Which chemical reaction is involved in the corrosion of iron?
Questions from Previous papers
21.Why potato chips manufacturers fill the packet of chips with nitrogen gas?
22. Identify the substance oxidised and reduced in the chemical reaction:
Mn O2 + 4 HCl ——> Mn Cl2 + Cl2 + 2H2O
23.Can a displacement reaction be a redox reaction? Explain with example.
24.Give an example of an endothermic reaction.
25.Give an example of photochemical reactions.
26.State a reaction in which SO2 acts as an oxidising agent.
27.Write the chemical equation for the reaction of hot aluminium with steam.
28.A green layer is gradually formed on a copper plate left exposed to air for a week
in a bathroom. What could this green substance be?
29.Write the chemical equation to represent the reaction taking place when copper
oxide is heated in a stream of hydrogen.
ACIDS, BASES AND SALTS
01. What is an indicator? Name three common indicators.
X (CBSE)
Question Bank (Physical Science)
Page 11 of 18
02. Name the acid- base indicator extracted from lichen.
03. What is an olfactory indicator? Name two olfactory indicators.
04. Which gas is usually liberated when an acid reacts with a metal? Illustrate with an
example. How will you test the presence of this gas?
05. Why should curd and other sour food-stuffs not be kept in copper and brass
vessels?
06. What happens when an acid reacts with a
(a) metal (b) metal carbonate
(c) metal hydrogen carbonate (d) metal oxide and (e) base? Give equations.
07. What is a neutralization reaction? Explain with an example.
08. What are organic acids and mineral acids? Give examples.
09. Name two strong acids and two weak acids.
10. Which element is common to all (a) acids and (b) bases?
11. Name one natural source for each of the following acids:
(a) Citric acid (b) Oxalic acid
(c) Lactic acid
(d) Tartaric acid
12. Why does an aqueous solution of acid conduct electricity?
13. Why do acids not show acidic behaviour in the absence of water?
14. State some of the uses of mineral acids in industry.
15. Define an acid and a base. Give two examples of each.
16. Give the names and formulae of two strong bases and two weak bases.
17. What does pH of a solution signify? Three solutions A,B and C have pH values of
6, 4 and 10 respectively. Which of the solution is highly acidic?
18. What is the pH value of a neutral solution?
19. State the relation between hydrogen ion concentration of an aqueous solution and
its pH.
20. What is a universal indicator? For what purpose it is used?
21. Do basic solutions also have H+ (aq) ions? If yes, then why are these basic?
22. Which acid is produced on our stomach? What happens if there is an excess of
acid in the stomach? How can its effect be cured?
23. The soil in a field is highly acidic. Name two materials which can be added to this
soil to reduce its acidity.
X (CBSE)
Question Bank (Physical Science)
Page 12 of 18
24. Why should water be never added drop wise to concentrated sulphuric acid?
25. What happens during a bee sting? What is its remedy?
26. What is a salt? Give the names and formulae of any two salts. Also name the
acids and bases from which these salts may be obtained.
27. Write the chemical name and formula of common salt.
28. Why is sodium chloride required in our body?
29. Name the raw material used for the production of caustic soda.
30. Write the chemical name and formula of
(a) caustic soda (b) washing soda (c) baking soda
(d) bleaching power
(e) plaster of Paris
31. Explain why, chlorine is used for sterilizing drinking water supply.
32. What happens when sodium hydrogencarbonate is strongly heated?
33. Name an acid which is present in baking powders.
34. Which compound is used as an antacid in medicine- NaHCO3 or Na2CO3?
35. How does baking powder differs from baking soda?
36. What does a soda-acid type fire extinguisher contain?
37. Explain the action of baking powder in the making of cake. Write equation of the
reaction involved.
38. What are the materials used for the preparation of bleaching power?
39. What is gypsum? What happens when it is heated to 1000C?
40. What will happen if heat is not controlled while preparing plaster of Paris?
41. What is meant by ‘water of crystallization’? Give an example.
42. What is meant by ‘hydrated’ and ‘anhydrous’ salts? Give examples.
Metals and Non-Metals
01. What are metals and non-metals? Name five metals and five non-metals.
02. Name one metal and one non-metal which exist in liquid state at room
temperature.
03. Name the most abundant metal and non-metal in the earth’s crust.
X (CBSE)
Question Bank (Physical Science)
Page 13 of 18
04. Name one metal which has a low melting point.
05. Name the metal which is the best conductor of heat and electricity.
06. Name the metal which is the poorest conductor of heat.
07. Why do metals appear to be dull? How can their brightness be restored?
08. Name a non-metal which conducts electricity.
09. Name a non metal having luster.
10. Name a non metal having a very high melting point.
11. Name a non-metal which is extremely hard.
12. State any five physical properties of metals and non-metals.
13. What happens when a strip of zinc is immersed in a solution of copper sulphate?
14. A copper coin is kept immersed in a solution of silver nitrate for some time. What
will happen to the coin and the colour of the solution?
15. What happens when iron nails are put into copper sulphate solution?
16. Why sodium is kept immersed in kerosene oil?
17. What are amphoteric oxides? Give examples.
18. Why does aluminium not react with water under ordinary conditions?
19. Write the chemical properties of metals and non-metals.
20. What is aqua-regia? Can it dissolve gold or platinum metals?
21. State five uses of metals and non-metals.
22. What is an ion? What is the nature of the charge on (i) a cation, (ii) an anion?
23. Write down the electronic configuration of (i) magnesium atom (ii) sulphide ion.
24. What is an ionic bond? What type of bond is present in oxygen molecule?
25. What is a covalent bond? What type of bond exist in: (i)CCl4 (ii) CaCl2?
26. What would be the electron dot structure of carbon dioxide?
27. Draw the electron –dot structure of the following compounds and state the type of
bonding in each case: (a) CO2
(e) N2
(f) CaCl2
(b) MgO
(c) KCl
(d)CaO
(g) MgCl2
28. Compare the properties of ionic compounds and covalent compounds.
29. Explain why, ionic compounds conduct electricity in solution whereas covalent
compounds do not conduct electricity.
X (CBSE)
Question Bank (Physical Science)
Page 14 of 18
30. Define the terms; (i) mineral (ii) ore, and (iii) gangue.
31. Name two metals which occur in nature in free state as well as in combined state.
32. Name one ore each of (i) zinc (ii) mercury (iii) sodium (iv) aluminium (v) iron
and (vi) copper and give their chemical formulae.
33. Describe with one example, how moderately reactive metals are extracted.
34. Explain how, mercury is extracted from its sulphide ore. Give equations of the
reactions involved.
35. What is thermite reaction? Explain with the help of an equation. State one use of
this reaction.
36. What is meant by refining of metals? Explain how metals are refined by the
electrolytic process.
37. What is meant by calcination and roasting? Give the reactions involved in it.
38. What is corrosion? Name any two metals which do not corrode easily.
39. What is meant by galvanization? What is it done?
40. Name five methods of preventing rusting of iron.
41. Why silver, gold and platinum are used to make jewellery?
42. Name two metals which are highly resistance to corrosion.
43. What is meant by anodizing?
44. Give the reason why copper is used to make hot water tanks but steel is not.
45. What is an alloy? Give two examples of alloys. How is an alloy made?
46. What is an amalgam?
47. How many carats is pure gold? Why is pure gold not suitable for making
ornaments?
Carbon and its Compounds
01. Name the three allotropes of carbon.
02. What is the unique property of carbon atom? How is this property helpful to us?
03. Explain why diamond is hard while graphite is soft.
04. What are the differences between diamond and graphite?
X (CBSE)
Question Bank (Physical Science)
Page 15 of 18
05. What is buckminsterfullerence?
06. What are hydrocarbons? Give the general formula of an (i) alkane (ii) alkene (iii)
alkyne and (iv) alkyl group.
07. Explain the meaning of saturated and unsaturated hydrocarbons with examples.
08. Write the electron-dot structure for : (i) ethane (ii) ethene, and (iii) ethyne.
09. Write the molecular formula and structure of (i) cyclohexane (ii) benzene.
10. Write the structural formula of (i) propene (ii) propyne and (iii) butane.
11. Explain the term ‘isomers’. Give one example.
12. What is a homologous series? Explain with an example.
13. The molecular formula of a hydrocarbon is C10H18. Name its homologous series.
14. What is meant by a functional group? Explain with an example.
15. Write three common functional groups present in organic compounds, Give their
symbols and formulae.
16. Name the functional group present in the following compounds.
CH3COOH
(ii) CH3CH2CHO
(iii) C2H5OH
(i)
(iv) CH3COCH2CH3
(v) CH3CH2CH2OH (vi) CH3CH2COOH
17. Draw the structures of (i) chlorobutane (ii) bromopentane.
18. Give the common name and IUPAC name of C2H5OH.
19. Draw the structures for the following compounds: (a) Ethanal (b) Propanal (c)
Butanal (d) Pentanal (e) Propanone (f) Butanone (g) Ethanoic acid
20. Name two fossil fuels. Why they are called as fossil fuels?
21. What happens when carbon burns in air? Write the chemical equation of the
reaction which takes place.
22. What makes the candle flame yellow and luminous?
23. Why are carbon and its compounds used as fuels for most applications?
24. How would you test for an alcohol? State any two uses of ethanol.
25. How would you distinguish between an alcohol and a carboxylic acid by chemical
test?
26. What is a soap? Name one soap. Describe the structure of a soap molecule with
the help of a diagram.
X (CBSE)
Question Bank (Physical Science)
Page 16 of 18
27. What is a detergent? Name one detergent.
28. Give any two differences between soaps and detergents.
29. Why have detergents replaced soap as a washing agent?
30. Why is soap not suitable for washing clothes when the water is hard?
Periodic Classification of Elements
01. What is Newlands’ law of octaves? Explain with an example. What were its
limitations?
02. Did Dobereiner’s triads also exist in the columns of Newlands’ law of Octaves?
Explain your answer.
03. State Mandeleev’s periodic law. Describe two anomalies of Mandeleev’s periodic
classification of elements.
04. Which group of elements was missing from Mandeleev’s original periodic table?
05. State the merits of Mandeleev’s classification of elements.
06. Why did Mandeleev leave some gaps in his periodic table of elements?
07. State modern periodic law.
08. How many periods and groups are there in the long form of the periodic table?
09. What is the significance of atomic number in the modern classification of
elements?
10. How could the modern periodic law remove various anomalies of Mandeleev’s
periodic table?
11. What are the characteristics of periods?
12. What are the characteristics of groups?
13. State one reason for keeping fluorine and chlorine in the same group of the
periodic table.
14. What are the merits of the modern periodic table of elements?
15. What are the advantages of the periodic table?
X (CBSE)
Question Bank (Physical Science)
Page 17 of 18
16. An element X belongs to 3rd period and group 2 of the periodic table. State:
(a) number of valence electrons (b) valency (c) metal or non-metal (d) name of
the element.
17. The elements A, B, C and D belong to groups 1, 2, 14 and 17 respectively of the
periodic table. Which of the following pairs of elements would produce a covalent
bond?
(a) A and D
(b) C and D
(c) A and B (d) B and C
(e) A and C
18. An element X from group 2 of the periodic table reacts with an element Y from
group 17 to form a compound.
(a) What is the nature of the compound formed?
(b) State whether the compound formed will conduct electricity or not.
(c) Give the formula of the compound formed
(d) What is the valency of element X?
(e) How many electrons are there in the outermost shell of an atom of element Y?
X (CBSE)
Question Bank (Physical Science)
Page 18 of 18