Magnetism and Electromagnetism
4 marks · NormalA student uses the following measurements from a transformer: input current = 0.3 A, input voltage = 230 V, output current = 3.0 A. The transformer is 100% efficient.
Calculate the output voltage of the transformer.
State the correct SI unit for current and for voltage.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 23 V
(b) Ampere (A) for current, Volt (V) for voltage.
Common mistakes: using wrong ratios
Show mark scheme and worked solution
Marking points
B8a (a) · 1 mark · Uses input power = output power: VpIp=VsIs (1).
B8b (a) · 2 marks · Correct substitution and calculation: 230 x 0.3 = Vs x 3.0; Vs = 23 V (2).
B8c (b) · 1 mark · States Ampere (A) and Volt (V) as correct SI units.
Worked solution
b) Ampere (A) is the SI unit for current; Volt (V) is the SI unit for voltage.