A transformer has 100 turns in primary and 200 turns in secondary. If primary voltage is 120 V, the secondary voltage is: MCQ with Answer and Explanation
A transformer has 100 turns in primary and 200 turns in secondary. If primary voltage is 120 V, the secondary voltage is:
A. 120 V
B. 60 V
C. 240 V
D. 480 V
Answer: Option C
Solution (By JKSSB Mock Tests)
Transformer voltage ratio: V_s/V_p = N_s/N_p, where N is number of turns. Thus V_s = V_p × (N_s/N_p) = 120 V × (200/100) = 240 V. This assumes ideal transformer (no losses). Step-up transformer (N_s > N_p) increases voltage. Memory aid: 'Turns ratio = voltage ratio'. This direct formula application is frequent in competitive exams. Always verify if transformer is step-up or step-down from turn counts. Note: Current ratio is inverse: I_s/I_p = N_p/N_s for power conservation (V_pI_p = V_sI_s).
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