Question

A current of 2 A is flowing at 220 V in the primary
coil of a transformer. If current in the secondary
coil is 1 A and efficiency of the transformer is 80%
then the voltage produced in the secondary coil will
be

(1) 176 V
(2) 352 V
(3) 528 V
(4) 220 V
​

Answer 1

Answer:

Current on primary (input) coil I

p

=5A

Voltage in primary coil V

p

=220V

Voltage in secondary coil V

s

=2200V

Output power is half of the input power i.e. P

s

=0.5P

p

∴ V

s

I

s

=0.5V

p

I

p

∴ 2200×I

s

=0.5×220×5

⟹ I

s

=0.25A

Answer 2

for primary coil

p=vi=220×2 =440

for secondary coil

80% p =v×1A

=80/100×440=v×1

v=44×8=352v