Problem 6: A resistor of 50 Ω has a P.D of 100 V, D.C. across 1 hour. Calculate (a) power and (b) energy.

Solution

Given                    Resistance = R = 50    P.D = V = 100 V                  time = 1 hour

Required              Power =?                                           Energy =?

Strategy: (a) Since Power = VI, we should first find the current in the resistor. I can be found by applying Ohm’s law,        I = V/R

Put the values
I = 100/50 = 2 amp

So now to find the power we put the value of current in the above formula for power calculation.

P = 100 * 2 = 200 watt.

(b) Energy is the work done in the circuit and given by Work = P * time. Put the values