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GCSE Standard Questions: Electric Circuits

Q1. (a) Draw a diagram to show how three 1.5 V cells should be connected together to give a potential difference of 4.5 V.

[2 marks]

for correct symbol for a cell

for correctly drawn in series

(b) A student built the circuit shown in the diagram below:

(i) Calculate the resistance of the complete circuit

V = IR

R = V/I

R = 12/1.6

R = 7.5 Ω

(3 marks)

(ii) Calculate the resistance of resistor Q

7.5 - 3.5 = 4.0 Ω

(1 mark)

(c) The student rebuilds the circuit above, this time putting the two resistors in parallel instead of series.

(i) What happens to the total resistance of the circuit?

Tick one box.

It increases  
It decreases
It stays the same  

(1 mark)

(ii) Explain your answer.

the current would be higher (for the same p.d.) or

there is now more than one path for charge to flow or

the total resistance is always less than the smallest individual resistance

(1 mark)

(Total 8 marks)