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Question
60 joules of heat was dissipated in a resistor when 20 C flowed for 5 s. Calculate:
(a) P.d. across the resistor,
(b) Resistance of the resistor, and
(c) Average power dissipated in the resistor.
Solution
Given, heat dissipated= 60 joules, charge Q = 20 C, time t= 5s
(a) P.d. across the rsistor, V = `"W"/"Q"= 60/20 = 3 "V"`
(b) Power = `"W"/"t" = "V"^2/"R"`
R = `"V"^2 xx "t"/"W" = (3)^2 xx 5/60 = 0.75 Omega`
(c) Power dissipated, P = `"W"/"t" = 60/5 = 12 "watt"`
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