Q 12-03-301JEE MainJEE Main 2025 (3 Apr, Shift 2)Easy
A motor operating on $100\ \text{V}$ draws a current of $1\ \text{A}$. If the efficiency of the motor is $91.6\%$, then the loss of power in units of cal/s is:
Answer: (C) $2$
Input power $= VI = 100\ \text{W}$; useful output $= 91.6\ \text{W}$.
Power lost $= 8.4\ \text{W} = 8.4\ \text{J/s} = \dfrac{8.4}{4.2}\ \text{cal/s} = 2\ \text{cal/s}$.
Solution by Sreeraj P, M.Sc Physics