The commercial unit of electrical energy is:
- Joule
- Watt
- Kilowatt-hour
- Volt-ampere
Answer: Kilowatt-hour
1 kWh = energy consumed by a 1 kW device running for 1 hour = 3.6×10⁶ Joules. Electricity bills use kWh. Understanding units is crucial for numerical problems. [[NCERT Physics Class 10]]