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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 220 V (Mains). If the main current is 0.5 A, the efficiency of the transformer is approximately

A

`95% `

B

`99% `

C

`90% `

D

`96% `

Text Solution

Verified by Experts

The correct Answer is:
C
The efficiency of the transformer is
`eta = (" Output power" (P_("out")))/("Input power" (P_("in")))xx 100`
Here, `P_("out") = 100 W, P_("in") = (220V) (0.5 A) = 110 W. `
`therefore eta = (100 W)/( 110 W) xx 100 = 90%`
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