Question

An electric bulb of 100 Watt operates 10 hour a day. What is the cost of energy to operate it for one day at Rs. 6 per kWh?
1. Rs. 60
2. Rs. 600
3. Rs. 0.6
4. Rs. 6

Answer 1

Correct Answer - Option 4 : Rs. 6

CONCEPT:

• Electric energy: The form of energy due to the flow of electrons is known as electric energy.
• The daily use appliances are given in power.

Energy = Power × time

• To calculate the cost of energy for electrical energy consumption, we use

Cost of energy = Rate of energy (in Rs per KWh) × total power used (in KW) × time (in hr)

EXPLANATION:

Given that P = 100 Watt = 0.1 KW; Time = 10 hours in one day

Rate of energy = Rs. 6 per kWh

So Cost of energy = Rate of energy (in Rs per KWh) × total power used (in KW) × time (in hr)

Cost of energy = 6 × 0.1 × 10 = 6 Rs

Hence the correct answer is option 4.