Question

An electric iron of resistance 20ohm is used across 1000v for 30 sec. If heat generated is 15000 joules. How long is iron used

Answer 1

V=IR

1000=I×20

1000/20=I

50A=I

H=I^2×R×T

15000=50^2×20×T

15000=2500×20×T

15000=50,000×T

15000/50,000=T

15/50=T

0.3 = T

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