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

1

(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

An electric current can produce

1

(a)

heating effect

(b)

chemical effect

(c)

magnetic effect

(d)

chemical, heating and magnetic effects

An electrolyte is

1

(a)

a metal

(b)

a solution

(c)

a liquid that conducts current

(d)

All of the above

The solution that can conduct electricity is of

1

(a)

pure water

(b)

water and acid solution

(c)

water and salt solution

(d)

Both (b) and (c)

Which one of the following solutions will not conduct electricity

1

(a)

Lemon juice

(b)

Vinegar

(c)

Tap water

(d)

Vegetable oil

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

1

(a)

electroplating

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

1

(a)

acids, bases and salts

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

1

(a)

good conductor

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

1

(a)

attraction/shining

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

1

(a)

electroplating

During electroplating, the object to be electroplated is made anode

1

(a) True

(b) False

Tester is used to test the conductivity of liquid.

1

(a) False

(b) True

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

1

(a) False

(b) True

Poor conductors also allow electricity to pass under certain conditions.

1

(a) False

(b) True

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

1

(a) False

(b) True

Will the solution of sugar in distilled water conduct electricity?

2

(a)

Name the effect of current responsible for the glow of the bulb in an electric circuit.

2

(a)

When a compass needle is brought near a current carrying wire, then what happens?

2

(a)

Mention the name of three liquids which can conduct electricity

2

(a)

What happens when common salt is added to distilled water?

2

(a)

Does pure water conduct electricity? If not, what can we do to make it conducting?

3

(a)

Boojho made the circuit as shown in figure. He wanted to observe what happens when an electric current is passed through water. But he forgot to add a few drops of lemon juice to water. Will it make any difference to his observations? Explain

3

(a)

The bulb glows when the electric current passes through it. Explain why.

3

(a)

Fill the following table and classify the liquids with the help of a tester.

S.No.	Material	Compass needle shows deflection (YES/NO)	conductor/Insulator
1	Lemon juice
2	Vinegar
3	Tap water
4	Vegetable oil
5	Milk
6	Honey

3

(a)

Paheli wants to deposit silver on an iron spoon. She took silver nitrate (AgNO₃) solution in a beaker and set up a simple circuit for electroplating. Which terminal of the battery should the spoon be connected to? What material should the other electrode be made of?

3

(a)

You are provided with a magnetic compass, an empty matchbox, a battery of two cells and connecting wires. Using these objects, how will you make a tester for testing an electric circuit? Draw the necessary circuit diagram and explain.

5

(a)

Observing that the bulb does not glow in the circuit shown in Fig. (a) Boojho changed the circuit as shown in Fig. (b). He observed deflection in the magnetic compass.

(a) What does the deflection in magnetic compass indicate?
(b) Why did the bulb not glow in Fig. (a)?
(c) What would be the effect of increase in the number of turns in the coil wound around the magnetic compass in Fig. (b)?

5

(a)