The electricity meters in houses measure energy unit consumed in

Analyze the question: The question asks which unit household electricity meters use to measure the energy consumed.

Explain the concept:

• Energy = Power × Time.
• The SI unit of energy is the joule (J), but 1 joule is far too small for billing homes.
• So electricity companies (such as those that supply NEPA/PHCN, now DisCos) use a larger unit: the kilowatt-hour (kWh), also called "one unit" of electricity.

Solution:

1. A 1 kW appliance running for 1 hour uses 1 kWh.
2. 1 kWh = 1000 W × 3600 s = 3,600,000 J = 3.6 MJ.

Now check the other options:

• Volt (B): the unit of potential difference (voltage), not energy.
• Ampere (C): the unit of electric current.
• Coulomb (D): the unit of electric charge.

Only the kilowatt-hour measures energy consumed.

Answer: The correct option is A. kilowatt-hour.

Tip: Remember that "kilowatt-hour" is power (kW) multiplied by time (h), so it is energy. If you see "hour" attached to a power unit, think energy. Also remember that V, A and C are all electrical quantities but are not energy units. Your electricity bill and prepaid meter ("units") are in kWh.