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A transformer is used to light a 100 W a...

A transformer is used to light a `100 W` and `110 V` lamp from a `220V` mains. If the main current is `0.5 A`, the Efficiency of the transformer is approximately:

A

`96%`

B

`90%`

C

`99%`

D

`95%`

Text Solution

Verified by Experts

The correct Answer is:
B
Given, output power = 100 W
V=220V, I=0.5A
We know that,
Efficiency = `("Output power")/("Input power") xx 100% = 100/(220 xx 0.5) xx100 =90%`
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