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Question
A transformer lowers e.m.f. from 220 V to 15 V. If 400 W power is given in primary, calculate (i) the current in primary coil and (ii) the current in secondary coil.
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Solution
(i) We know that Power = Ip × Ep
or 400 = Ip × 220
∴ Ip = 1.8 A
(ii) Using Ip × Ep = Is × Es
∴ `"I"_"s" = ("I"_"p" xx "E"_"p")/"E"_"s"`
`"I"_"s" = (1.8 xx 220)/15`
= 26.4 A.
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