For domestic tariff, one unit of electrical energy consumption is equal to:

Correct option is A

The correct answer is: (a) 1 kilowatt-hour
Explanation:
· One unit of electricity is defined as 1 kilowatt-hour (kWh), which equals 1000 watts used for 1 hour.
· It is the standard billing unit for domestic electricity consumption.
Information Booster:
· 1 kWh = 1000 watt × 3600 seconds = 3.6 × 10⁶ joules.
· Calculated as: Power (kW) × Time (hr).
· Used by power companies for billing and tariff.
· Measured using an electricity meter.
· Common appliances: 1 kWh = ~ usage of 1 ton AC for 1 hour.
· Monitored by State Electricity Boards (SEBs).
Additional Information:
· Volt ampere hour – Used in AC circuit apparent power, not energy.
· Kilojoule hour – Non-standard for energy billing.
· Milliamp hour – Used in battery capacity, not energy consumption.