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A step down transformer of efficiency `80%` is used on a 1000V line to deliver a current of 20 A at 120 V at the secondary coil. What is the current drawn from the line?A. 0.3 AB. 30 AC. 2.4 AD. `2 A` |
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Answer» Correct Answer - D `V_(p) = 1000 V , V_(s) = 120 V and I_(s) = 20 A` For an ideal transfomer, `V_(p) xx I_(p) = V_(s) xx I_(s)` `:. I_(p) = (120 xx 20)/(1000) = 2.4 A` But for the given transformer, the efficiency is `80%` `:. I_(p)` should be `2.4 xx 100/80 = 3A`. |
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