Electric currents and it's effects

Combination of two or more cells is called ___________

• Cell

• Battery

• Both (a) and (b)

• All of these

When an electric current flows through a copper wire AB as shown in figure, the wire

• (a) deflects a magnetic needle placed near it.

• (b) becomes red hot

• (c) gives electric shock

• (d) behaves like a fuse.

Answer explanation

A current carrying wire acts as a magnet with a magnetic field around it, the strength of which depends upon the amount of current passing through it.

Draw the diagram of a open circuit in symbols

Answer explanation

The following is the correct diagram of a open circuit in symbols

(i) Our body is a (a)   of electricity

(Please don't use capital letters)

(ii) An electric cell produces electricity from the (a)   in it

(Please don't use capital letters)

Unscramble the following words:

1) TBTAYER

(All typed answers should be in capital letters)

(a)  

2) HTRCO

(All typed answers should be in capital letters)

(a)  

Three bulbs A, B, C are connected in a circuit as shown in figure. When the switch is ‘ON’

• (a) bulb C will glow first.

• (b) bulb B and C will glow simultaneously and bulb A will glow after some time.

• (c) all the bulbs A, B and C will glow at the same time.

• (d) the bulbs will glow in the order A, B and C.

Answer explanation

As soon as the switch is ‘ON’, current can be found everywhere in the circuit.

When a switch is in OFF position,

(i) circuit starting from the positive terminal of the cell stops at the switch.

(ii) circuit is open.

(iii) no current flows through it

(iv) current flows after some time.

Choose the combination of correct answer from the following.

• (a) all are correct

• (b) (ii) and (iii) are correct

• (c) only (iv) is correct

• (d) only (i) and (ii) are correct

Name the device which can be used in place of fuse in domestic wiring

• MCB

• MCD

• DCB

• BCM

Answer explanation

Miniature circuit breaker (MCB) is used these days in place of electric fuses in electrical circuits.