Question

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:(a) 300 V, 15A(b) 450 V, 15A(c) 450V, 13.5A(d) 600V, 15A

Answer 1

Answer:

B) 450V. 15A

Explanation:

Efficiency = 90% (Given)

Voltage = 200V (Given)

Current in secondary coil = 6A (Given)

Initial power = 3000W (Given)

Since the efficiency is 90%, thus the final power = 3000×90/100 = 2700

Thus,

V1I1 = 3000W

V1I1 = 2700W -- (1)

So, V2 =2700/6 =900/2 = 450V and

I1 =3000/200

=15A

Thus. the voltage across the secondary coil and the current in the primary coil respectively are 450V and 15A