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, 13.5 A
D. 600 V, 15 A

Answer

B

Explanation

Initial power=3000W
As efficiency is 90%, then final power
`=3000xx(90)/(100)=2700W`
`implies[(V_(1)l_(1)=3000W),(V_(2)l_(2)=2700W)]` . . . (i)
So, `V_(2)=(2700)/(6)=(900)/(2)=450V`
and `l_(1)=(3000)/(200)=15A`