Question

A copper voltameter is connected in series with a coil of resistance $10\Omega$. When a steady current is passed through the circuit, $0.297g$ of copper is found to be deposited at the cathode in $15min$. The electrochemical equivalent of copper is $3.3\times {10}^{-7}kg{C}^{-}$. Heat liberated in the coil is:

• A. $900J$
• B. $90J$
• C. $9J$
• D. $9kJ$

Answer 1

Answer: (D)

$9kJ$

$I=\frac{m}{Zt}=\frac{297\times {10}^{-6}}{3.3\times {10}^7\times 15\times 60}=1A$
$H=I^{2}Rt=1\times 10\times 15\times 60$
$=9000J=9kJ$