Very Short Question and Answers - Electric Power

Electric power is the rate at which electrical energy is consumed or produced by an appliance or circuit.

The SI unit of electric power is the watt (W).

The formula is P = V × I, where P is power, V is voltage, and I is current.

Electric power can be calculated as P = I² × R, where I is current and R is resistance.

P = V² / R, where V is voltage and R is resistance.

1 kilowatt (kW) = 1000 watts (W).

1 kWh = 3.6 × 10⁶ joules (J).

Power = 220 V × 0.5 A = 110 W.

Power = (5 A)² × 20 Ω = 25 × 20 = 500 W.

Power = (200 V)² / 100 Ω = 40,000 / 100 = 400 W.

Kilowatt (kW) and megawatt (MW).

Energy consumed (in kWh) = Power (in kW) × Time (in hours).

Energy = 2 kW × 3 h = 6 kWh = 6 × 3.6 × 10⁶ J = 21.6 × 10⁶ J.

Total units = 1.5 kW × 2 h × 30 = 90 kWh.

Cost = 90 × ₹6 = ₹540.

Power = 12 V × 10 A = 120 W.

Energy = 0.1 kW × 10 h = 1 kWh.

Energy = 1 kWh = 3.6 × 10⁶ J.

Power = (250 V)² / 500 Ω = 62,500 / 500 = 125 W.

It means the bulb consumes 100 watts of power when operated at 220 volts.