Questions on Electric Circuits

Q3.

(a) The drawing below shows the parts of a torch.

(i) Paul closed the switch. Why did this turn on the torch?

That action completed the circuit so a current could flow in the bulb.

1 mark

(ii) Draw a labelled series circuit for the torch. Use the correct symbols for the bulb, battery of two cells and the switch and clearly label each one.

one for each correct labelled symbol

one for the series circuit - no gaps between symbols!

4 marks

(b) The drawings below show two other torches. In both torches, the bulbs will not light even when Paul closes the switches. Look carefully at the drawings.

(i) Why is the circuit of torch A not complete?

The filament of the bulb is broken, causing a gap within the bulb itself.

1 mark

(ii) What could you do to torch B to get the bulb to light?

Turn one of the cells round - the positive terminals are connected together the positive should connect to a negative.

1 mark

(c) When Paul bought his torch there was a paper strip between the contacts of the switch as shown below. Paul had to remove the paper strip before he could turn the torch on. Give the reason for this.

Paper is an insulator so it prevents the current flow.

1 mark

maximum 8 marks