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

Options

A. `300 v 15 A`
B. `450 V, 15 A`
C. `450 V, 135 A`
D. `600 V, 15 A`

Answer

B

Explanation

Power output, `P_(s) = 3 kW x (90)/(100) = 2.7 kW`
`V_(s) = (P_(s))/(I_(s)) = (2.7 kW)/(6 A) = 450 W`
`I_(s) = (P_(i))/(V_(i)) = (3 kW)/(200 V) = 15 A`