Questions on Electric Circuits
Q3.
(a) The drawing below shows the parts of a torch.
![](electricitydiagram3.png)
(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. ![](../../../graphics/symbols/nuclides/ticksmall.png)
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.
![](electricitydiagram3c.png)
![](../../../graphics/symbols/nuclides/ticksmall.png)
![](../../../graphics/symbols/nuclides/ticksmall.png)
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.
![](electricitydiagram3a.png)
(i) Why is the circuit of torch A not complete?
The filament of the bulb is broken, causing a gap within the bulb itself. ![](../../../graphics/symbols/nuclides/ticksmall.png)
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.
![](electricitydiagram3b.png)
Paper is an insulator so it prevents the current flow. ![](../../../graphics/symbols/nuclides/ticksmall.png)
1 mark
maximum 8 marks