Question Set B

CBSE 8th Standard Science Chemical Effects of Electric Current Sample Question Papers Study Material - QB365

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Questions:

Fill up / 1 Marks

22 x 1 = 22

________ does not corrode easily.

An electric lamp glows due to ______ effect of electric current.

________ water is a poor conductor of electricity.

_______ is an example of an electrolytic solution.

LED glows even when a.............electric current passes through it.

If we pass current through a conducting solution then..............effect takes place

Electroplating of.............is done on objects like water taps and cycle bell to give them a shiny appearance.

The conducting solutions used in...........process are polluting wastes.

Electroplating is used to give more...............to the cheap objects.

10.

When electric current is passed through copper sulphate solution, copper gets deposited on the plate connected to the.........terminal of the battery.

11.

Small amount of a mineral salt present naturally in water makes it a.......of electricity

12.

Most of the conducting liquids are the solutions of.................,.............,and..........

13.

Flow of negatively charged electrons is called...............

14.

One of the most common applications of chemical effect of electric current is..........

15.

Distilled water is..............of the electricity

16.

The closed path through which the current flows is called..........

17.

The object to be electroplated is taken as.........electrode

18.

Materials which do not allow an electric current to pass through them are called..............

19.

A liquid that conducts electricity due to the presence of ions is called...........

20.

The process of depositing a layer of any desired metal on another material by means of electricity is called...........

21.

If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the.................terminal of the battery.

22.

The passage of an electric current through a solution causes........effects.

Multiple Choice Question

16 x 1 = 16

23.

Which of the following metals is used in electroplating to make objects appear shining?

(a)

Iron

(b)

Copper

(c)

Chromium

(d)

Aluminium

24.

Boojho's uncle has set up an electroplating factory near his village. He should dispose off the waste of the factory

(a)

in the nearby river

(b)

in the nearby pond

(c)

in the nearby corn field

(d)

according to the disposal guidelines of the local authority

25.

The process of depositing a thin layer of any superior metal over an object of a cheaper metal with the help of electricity is called

(a)

electro refining

(b)

electro-metallurgy

(c)

electroplating

(d)

None of the above

26.

Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B as shown in figure.

They found that the bulb in the set up A glows more brightly as compared to that of the set up B. You would conclude that

(a)

higher current is flowing through the circuit in set up A

(b)

higher current is flowing through the circuit in set up B

(c)

equal current is flowing through both the circuits

(d)

the current flowing through the circuits in the two set ups cannot be compared in this manner

27.

Which of the following solutions will not make the bulb glow in figure?

(a)

Sodium chloride

(b)

Copper sulphate

(c)

Silver nitrate

(d)

Sugar solution in diluted water

28.

The device which can be used to detect very small current flowing in an electric circuit is

(a)

LEAD

(b)

MCB

(c)

LED

(d)

None of these

29.

The presence of a small amount of impurities makes water

(a)

a good conductor of electricity

(b)

a bad conductor of electricity

(c)

pure

(d)

None of the above

30.

Which one of the following solutions will not conduct electricity

(a)

Lemon juice

(b)

Vinegar

(c)

Tap water

(d)

Vegetable oil

31.

The solution that can conduct electricity is of

(a)

pure water

(b)

water and acid solution

(c)

water and salt solution

(d)

Both (b) and (c)

32.

An electrolyte is

(a)

a metal

(b)

a solution

(c)

a liquid that conducts current

(d)

All of the above

33.

When electric current is passed through a conducting solution, there is a change of colour of the solution. This indicates

(a)

the chemical effect of current

(b)

the heating effect of current

(c)

the magnetic effect of current

(d)

the lightning effect of current

34.

Electrolytes conduct electricity due to the movement of

(a)

electrodes

(b)

atoms

(c)

electrons

(d)

ions

35.

Plastic wire is

(a)

an insulator

(b)

a conductor

(c)

Both (a) and (b)

(d)

None of these

36.

On passing electric current through solution of an electrolyte, the solution experiences

(a)

magnetic effect

(b)

heating effect

(c)

chemical effect

(d)

None of these

37.

An electric current can produce

(a)

heating effect

(b)

chemical effect

(c)

magnetic effect

(d)

chemical, heating and magnetic effects

38.

A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A, while it glows very dimly for liquid B. You would conclude that

(a)

liquid A is a better conductor than liquid B

(b)

liquid B is a better conductor than liquid A

(c)

both liquids are equally conducting

(d)

conducting properties of liquid cannot be compared in this manner

True or False

20 x 1 = 20

39.

Lemon juice shows deflection means that it is a good conductor.

(a)

False

(b)

True

40.

Poor conductors also allow electricity to pass under certain conditions.

(a)

False

(b)

True

41.

The bulb gets heated to a high temperature and it starts glowing when electric current passes through it.

(a)

False

(b)

True

42.

Tester is used to test the conductivity of liquid.

(a)

False

(b)

True

43.

Distilled water is poor conductor of electricity

(a)

False

(b)

True

44.

Only solids can conduct electricity

(a)

True

(b)

False

45.

Materials that do not allow electric current to pass through them easily are good conductors of electricity.

(a)

True

(b)

False

46.

Flow of electrons is called electric current.

(a)

False

(b)

True

47.

Plastics are the good conductors of electricity

(a)

True

(b)

False

48.

The chemical reaction brought about by an electric current may produce changes in the colour of solutions.

(a)

False

(b)

True

49.

The chemical effect of electric current is used in purification of salts.

(a)

True

(b)

False

50.

During electroplating, the object to be electroplated is made anode

(a)

True

(b)

False

51.

The passage of an electric current through a conducting liquid cases chemical reactions

(a)

False

(b)

True

52.

Most liquids that conduct electricity are solutions of acids, bases and salts.

(a)

False

(b)

True

53.

Electric bulb glows due to chemical effect of electricity.

(a)

True

(b)

False

54.

Distilled water conducts the electric current

(a)

True

(b)

False

55.

Some liquids are good conductors of electricity and some are poor conductors

(a)

False

(b)

True

56.

Electrolysis is a chemical change

(a)

False

(b)

True

57.

During the electrolysis of water, hydrogen gas is liberated at the anode

(a)

True

(b)

False

58.

Adding of sugar makes pure water conducting

(a)

True

(b)

False

Match the following

10 x 1 = 10

59.

Lemon juice

60.

LED

61.

Carbon rod

62.

A tester

63.

Copper and aluminium

64.

Electroplating

65.

Solution of distilled water and salt

66.

Closed path

67.

Conductor

68.

Insulator

1 Marks

11 x 1 = 11

69.

What is a tester?

70.

What is the ill effect of electroplating?

71.

How can we check magnetic effects of current?

72.

What are electrodes?

73.

What is distilled water?

74.

What is the magnetic effect of electric current?

75.

Which effect of current causes the bulbs to glow?

76.

What is electric current?

77.

Why is it dangerous to touch electrical appliances with wet hand?

78.

Give two examples of good conductors.

79.

What are good conductors of electricity?

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Answers Key:

Fill up / 1 Marks

22 x 1 = 22

()
plastic

()
heating

()
Distilled,

()
Copper sulphate solution

()
small

()
chemical

()
chromium

()
electroplating

()
attraction/shining

10.

()
negative

11.

()
good conductor

12.

()
acids, bases and salts

13.

()
electric current

14.

()
electroplating

15.

()
poor conductor

16.

()
circuit

17.

()
negative

18.

()
insulator

19.

()
electrolyte

20.

()
electroplating

21.

()
negative

22.

()
chemical

Multiple Choice Question

16 x 1 = 16

23.

24.

(d)
according to the disposal guidelines of the local authority

25.

26.

(a)
higher current is flowing through the circuit in set up A

27.

(d)
Sugar solution in diluted water

28.

29.

(a)
a good conductor of electricity

30.

(d)
Vegetable oil

31.

(b)
water and acid solution

32.

(b)
a solution

33.

(a)
the chemical effect of current

34.

(d)
ions

35.

(a)
an insulator

36.

37.

(d)
chemical, heating and magnetic effects

38.

(a)
liquid A is a better conductor than liquid B

True or False

20 x 1 = 20

39.

(a)
False

40.

(a)
False

41.

(a)
False

42.

(a)
False

43.

(a)
False

44.

(b)
False

45.

(b)
False

46.

(a)
False

47.

(b)
False

48.

(a)
False

49.

(b)
False

50.

(b)
False

51.

(a)
False

52.

(a)
False

53.

(b)
False

54.

(b)
False

55.

(a)
False

56.

(a)
False

57.

(b)
False

58.

(b)
False

Match the following

10 x 1 = 10

59.

()
Added to water to increase the conductivity

60.

()
Light Emitting Diodes

61.

()
Electrodes

62.

()
Detect the current

63.

()
Good conductor

64.

()
Prevents rusting

65.

()
Conduct current

66.

()
Electric circuit

67.

()
Copper

68.

()
Rubber

1 Marks

11 x 1 = 11

69.

()
The device which is used to check current is called tester

70.

()
The used conducting solution causes pollution

71.

()
By using magnetic compass.

72.

()
The metal rods dipped in liquid to which a cell is attached are called electrodes.

73.

()
The water that does not contain salts is called distilled water

74.

()
The electric current flowing in a wire produces the magnetic field around it. A current carrying conductor behaves like a magnet.

75.

()
Heating effect

76.

()
The flow of electric charge is called electric current.

77.

()
Our body is a good conductor of electricity and wet hands are also good conductors. Hence, by touching electrical appliances with wet hands electricity passes through our body and we feel a shock.

78.