Q. A hot electric iron has a resistance of $80\ \Omega\ $and is used on a $200\ V$ source. The electrical energy spent, if it is used for two hours, will be
A) $8000\ Wh$
B) $2000\ Wh$
C) $1000\ Wh$
D) $800\ Wh$
Explanation
(c) $Energy = \frac{V^{2}}{R}t = \frac{200 \times 200 \times 2}{80} = 1000\ Wh$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.