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Calculate the current drawn by the primary of a transformer, which steps down 200 V to 20 V to operate a device of resistance 10 Omega.Assume the efficiency of the transformer to be 80%. |
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Answer» SOLUTION :Here, `V_(p) = 200 V, V_(s) = 20V`, efficiency `eta = 80% = 80/100 = 0.8` and resistance in secondary circuit `R = 20 Omega` `therefore I_(s) = V/R = (20 V)/(20 Omega) = 1A` As efficiency `eta = ("OUTPUT")/("Input") =(V_(s).I_(s))/(V_(p).I_(p)) rArr I_(p) =(V_(s).I_(s))/(V_(p).eta) = (20 xx 1)/(200 xx 0.8) = 0.125 A` |
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