Q. A copper voltmeter is connected in series with a heater coil of resistance $0.1\Omega.$ A steady current flows in the circuit for twenty minutes and mass of $0.99\ g$ of copper is deposited at the cathode. If electrochemical equivalent of copper is $0.00033\ gm/C,$ then heat generated in the coil is
A) $750\ J$
B) $650\ J$
C) $350\ J$
D) $250\ J$
Explanation
(a) $m = Zi\ t\ \Rightarrow i = \frac{m}{Zt} = \frac{0.99}{0.00033 \times 1200} = 2.5A$
Hence heat generated in the coil is
$H = i^{2}Rt = (2.5)^{2} \times 0.1 \times 1200 = 750\ J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.