A transformer having efficiency of 90% is working on 200V

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A transformer having efficiency of 90% is working on 200V and 3kW power supply. If the current in the secondary coil is 6A, the voltage across the secondary coil and the current in the primary coil respectively are :

1. 300 V, 15A
2. 450 V, 15A
3. 450V, 13.5A
4. 600V, 15A

Correct Option: B

Efficiency η =	V_sI_s	⇒ 0.9 =	V_s(6)
	V_pI_p		3 × 10³

⇒ V_s = 450 V
As V_pI_p = 3000 so

I_p =	3000	=	3000	A = 15 A
	V_p		200