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GCSE Standard Questions: Electric Circuits

Q6. Here is a circuit diagram:

(a) Give the letter indicating the position a switch could be placed in, so that both lamps can be switched on or off at the same time.

M

[1 mark]

(b) Draw the circuit symbol for a switch.

 

 

[1 mark]

(c) In 30 seconds, 24 coulombs of charge flow through the battery.

Calculate the current in the battery.

I = Q/t

I = 24/30

I = 0.80 A

[3 marks]

(d) There is a potential difference of 3.6 V across the battery.

Calculate the energy transferred by the battery when 60 coulombs of charge flows through it.

E = QV

E = 60 x 3.6

E = 216 J

E = 220 J

The answer should be given to two significant figures as the data is given to only 2 sig figs. but in this question they did not deduct marks for leaving the answer at 3 sf.

[3 marks]

(e) Ragnar built Circuit X and Circuit Y shown in the circuit diagrams below.

The components used in each circuit were identical.

(i) How would the reading on the ammeter in Circuit Y compare to the reading on the ammeter in Circuit X?

[2 marks]

The ammeter reading in circuit Y would be lower, it would be a quarter of the value of the ammeter in circuit X.

(ii) How does the total resistance of Circuit Y compare with the total resistance of Circuit X?

The total resistance of circuit Y would be high, it would be a four times the total resistance of circuit X.

[2 marks]

(f) Ragnar then built another circuit:

(i) Write down the equation which links current, potential difference and resistance.

potential difference = current × resistance

or

V = IR

[1 mark]

(ii) There is a potential difference of 3.6 V across the lamp in the above diagram. The current through the lamp is 0.80 A

Calculate the resistance of the lamp.

R = V/I

R = 3.6/0.80

R = 4.5 Ω

[3 marks]

(Total 16 marks)