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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

`50%`

B

`90%`

C

`10%`

D

`30%`

Text Solution

Verified by Experts

Efficiency of transformer
`(eta) = (V _(S) I _(S))/(V _(P) I _(P)) xx 100`
`(V _(S) I_(S)) = ` Power in secondary coil = 100 W
`eta = (100)/( 220 xx 0.5) xx 100 = 90. 9~~90%`
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