Question
A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6 A, the voltage across the secondary coil and the current in the primary coil respectively are:
-
300 V, 15 A
-
450 V, 15 A
-
450 V, 13.5 A
-
600 V, 15 A
Solution
B.
450 V, 15 A
Initial power = 3000 W
As the efficiency is 90%, then final power = 
= 2700 W
That is,
... (i)
So, 
