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A transformer is used to light a 140 W, ...

A transformer is used to light a 140 W, 24 V lamp from 240 V AC mains. The current in mains cable is 0.7 A, find the efficiency of transformer.

A

`63.8%`

B

`74%`

C

`83.3%`

D

`48%`

Text Solution

Verified by Experts

The correct Answer is:
C
Output power = 140 W
Input power `= 240xx0.7=168 W`
Efficiency `=("output power")/("input power")xx100=(140)/(168)xx100=83.3%`
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