NCERT Solutions for Class 6 Science Chapter 12 Electricity And Circuits

Q1 ) Q.1 Fill in the blanks :
(a) A device that is used to break an electric circuit is called _______________.
(b) An electric cell has _______________ terminals.

Answer :

(a) A device that is used to break an electric circuit is called switch.

(b) An electric cell has two terminals.

Q2 ) Mark ‘True’ or ‘False’ for following statements:
(a) Electric current can flow through metals.( )
(b) Instead of metal wires, a jute string can be used to make a circuit.( )
(c) Electric current can pass through a sheet of thermocol.( )

Answer :

(a) Electric current can flow through metals.( T )


(b) Instead of metal wires, a jute string can be used to make a circuit.(F)

REASON : Jute is a bad conductor of electricity.


(c) Electric current can pass through a sheet of thermocol.( F )

REASON : Sheet of thermocol is a bad conductor of electricity

Q3 ) Explain why the bulb would not glow in the arrangement shown in Fig. 12.13.

Answer :

(1) The bulb would not glow in the arrangement because the circuit is not complete due to the presence of an insulator in the centre.

(2) A bad conductor or insulator does not allow to pass the electric current.

(3) So we can say that the circuit is open, and the bulb will not glow.

Q.4 Complete the drawing shown in Fig 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Answer :

To complete the given circuit, the free terminal of the cell should be connected to one end of the switch and the base terminal of the bulb should be connected to the other end of the switch as shown in the following figure.

Q.5 What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Answer :

(1) A switch is a simple device that is used to either break the electric circuit or to complete it.

(2) Electric gadgets that have switches built into them are microwaves, freezes, rice cookers, automatic electric iron, toasters etc.

Q.6 Would the bulb glow after completing the circuit shown in Fig. 12.9 if instead of safety pin we use an eraser?

Answer :

No, the bulb will not glow as the eraser is an insulator.

Hence, it will break the circuit.

Q.7 Would the bulb glow in the circuit shown in Fig. 12.11.

Answer :

Yes, the bulb would glow in the given circuit because the circuit is closed or complete.

Q.8 Using the“conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.

Answer :

(1) The object is a conductor because the bulb glows only when the conductor is used but not when the insulator is used.

(2) As conductor allows the electric current to pass through it and causes the bulb of the tester to glow.

Q.9 Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

Answer :

(1) An electrician uses rubber gloves while repairing an electric switch at your home because rubber gloves are insulators.

(2) This protects him from avoiding electric shocks.

(3) As rubber is a bad conductor of electricity so it does not allow the electric current to pass through it.

Q.10 The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

Answer :

(1) Plastic and rubber both are bad conductors of electricity.

(2) So, they do not allow current to pass through them.

(3) The handles of tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber cover on them so that they do allow the current to pass through them and save the electrician from any electric shock.