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Question
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
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Solution
The amount of heat (H) produced is given by the joule’s law of heating as H = Vlt
Where,
Current, I = 5 A
Time, t = 30s
Voltage, V = Current × Resistance
= 5 × 20
= 100 V
H = 100 × 5 × 30
= 1.5 × 104 J.
Therefore, the amount of heat developed in the electric iron is 1.5 × 104 J.
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