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GCSE Standard Questions: Electric Circuits

Q3. (a) The circuit diagram shows a lamp and an 18 Ω resistor connected in a series circuit.

 

(i) Calculate the potential difference across the 18 Ω resistor. Give the answer to two significant figures.

V = IR

V = 18 x 0.12

V = 2.16 V

V = 2.2 V (to 2 sig figs)

[4 marks]

(ii) Calculate the potential difference across the lamp.

V = 4.5 - 2.2 = 2.3 V

(Or 4.5 - 2.16 = 2.34V - that got you the marks too!)

[1 mark]

 

(b) The sketch graphs show the current-potential difference graphs for three electrical components, A, B and C.

(i) Which component, A, B or C is a lamp? C

[1 mark]

(ii) Which component, A, B or C is a diode? A

[1 mark]

(Total 7 marks)