Units (Magnetism & Electromagnetism)
4 marks · NormalA transformer has 300 turns on its primary coil and 1200 turns on its secondary coil. The voltage applied to the primary coil is 5.0 V a.c.
Calculate the voltage across the secondary coil.
If the transformer is 100% efficient and the current in the primary coil is 1.2 A, calculate the current in the secondary coil.
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(a) 20 V
(b) 0.3 A
Common mistakes: Incorrectly inverting the turns ratio
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Marking points
M1 (a) · 1 mark · Correct use of transformer equation:
A1 (a) · 1 mark · Correct calculation:
M2 (b) · 1 mark · Uses for 100% efficiency
A2 (b) · 1 mark · Correct calculation: (follow-through)
Worked solution