Q. An electric lamp is marked 60 W, 230 V. The cost of kilowatt hour of power is Rs 1.25. The cost of using this lamp 8 h a day for 30 days is
A) Rs 10
B) Rs 16
C) Rs 18
D) Rs 20
Explanation
(c) Cost $= \left( \ \frac{60 \times 8 \times 30}{1000} \right) \times 1.25 =$Rs 18.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.