Question

An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

Answer 1

The rate of heat produced by a device is expressed as power: \(P= I^2R\). Given,
Resistance \(R= 8 \ Ω\)
Current \(I = 15 \ A\)
\(P= (15)^2 \times 8 \)
\(P= 1800 \ J/s\)

The heater produces heat at a rate of \(1800 \ J/s.\)