An electric kettle is rated 2.2kW 220V. It the cost of electricity is ₹4 per unit (kwh), what is the cost of boiling water for 30 minutes?
Show answer & explanation
Correct answer: D
Explanation
Answer: ₹4.4
Explanation
Power of kettle = 2.2 kW
Time = 30 minutes = 0.5 hour
Energy consumed = Power × Time
= 2.2 × 0.5 = 1.1 kWh (units)
Cost per unit = ₹4
Total cost = 1.1 × 4 = ₹4.4
Additional Key Facts
Electrical energy is measured in kilowatt-hour (kWh), also called “unit.”
1 unit = 1 kWh = 1000 watts used for 1 hour.
Formula: Energy (kWh) = Power (kW) × Time (hours)
Electricity bill = Units consumed × Rate per unit
Potential Exam-Oriented Questions & Answers
Question: What is 1 unit of electricity equal to?
Answer: 1 kWh
Question: Formula for electrical energy consumption?
Answer: Power × Time