Rate of heat produced by a device is given by the expression for power as, \(P= I^2R\)
Where,
Resistance of the electric heater, \(R= 8 \ Ω\)
Current drawn, \(I = 15 \ A\)
\(P= (15)^2 \times 8 \)
\(P= 1800 \ J/s\)
Therefore, heat is produced by the heater at the rate of \(1800 \ J/s.\)
Power is defined as the rate of doing work. Electric power is the rate at which electrical energy is transferred through an electric circuit, i.e. the rate of transfer of electricity. The symbol for Electric Power is ‘P’. SI unit of electric power is Watt.
P = VI
From Ohm's Law, V = IR
Hence, Power can also be expressed as P = I2R