Q. An electric lamp is marked $60\ W,\ 230\ V.$ The cost of a $1\ kWh$ of energy is $Rs.\ 1.25.$ The cost of using this lamp $8\ hrs$ a day for 30 days is
A) $Rs.\ 10$
B) $Rs.\ 16$
C) $Rs.\ 18$
D) $Rs.\ 20$
Explanation
(c) Total$\ kWh\ $consumed$= \frac{60 \times 8 \times 30}{1000} = 14.4$
Hence cost $= 14.4 \times 1.25 = 18\ Rs$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.