CONCEPT: Power (P): The rate of work done by an electric current is called power. It is denoted by P. The SI unit of power is the watt (W). Power dissipation is given by: ⇒ P = V I = V2/R = I2 R Where V is the potential difference across resistance, I is current flowing and R is resistance. Heat dissipation/work done/Electrical energy is given by: ⇒ Heat dissipated (H) = Power (P) × Time (t) CALCULATION: For kettle: Given - Power (P) = 3 kW and time (t) = 10 minute = 1/6 hour The total energy consumed by the kettle would be: ⇒ Energy (H) = P × t = 3 kW × 1/6 hour = 0.5 kWh ------- (1) For lamp: Power (P) = 100 W and time (t) = 6 hour The total energy consumed by the lamp would be: ⇒ Energy (H) = P × t = 100 W × 6 hour = 600 Wh = 0.6 kWh ------- (2) For oven: Given - Power (P) = 5 kW and time (t) = 2 hour The total energy consumed by the oven would be: ⇒ Energy (H) = P × t = 5 kW × 2 hour = 10 kWh ------- (3) For lamp: Power (P) = 100 W and time (t) = 24 hour The total energy consumed by the lamp would be: ⇒ Energy (H) = P × t = 100 W × 24 hour = 2400 Wh = 2.4 kWh ------- (4) On comparing equations 1, 2,3, and 4, we get that oven consumes energy the most. Therefore option 3 is correct.