Question

Calculate the current drawn by primary coil of a transformer connected to 220 volt AC. it gives output of 20 volt. if this is used to operate a device of resistance 20 ohm.

$\eta = 80\%$
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Answer 1

Answer:

Here VP=200V,VS=20,RS=20Ω, efficiency (η)=80%

IS=VSRS=2010=1A

Efficiency η=VSISVPIP or 80100=200×1200×Ip

[∵=Power outputPower input]

or IP=0.125A