Electrical energy in kWh formula

Steps:

• Calculate power P = voltage (V) × current (I) in watts.
• Multiply power by time t in hours to get energy in watt-hours: E_wh = P × t.
• Convert to kilowatt-hours by dividing by 1000: E_kWh = E_wh / 1000.
• Substitute: E = (V × I × t) / 1000.

Why D is correct:

• It matches the standard formula for electrical energy, where power in kilowatts (V × I / 1000) multiplied by hours gives E in kWh.

Why the others are wrong:

• A: Uses seconds instead of hours, yielding joules rather than kWh.
• B: Subtracts 1000 without basis, incorrectly altering the energy calculation.
• C: Omits division by 1000, resulting in watt-hours instead of kWh.

Final answer: D