If a wire of resistance 20Ω is covered with ice (at 0°C) and a voltage of 210 V is applied across the wire, then the rate of melting of ice is:
Answer & explanation
Correct answer: option 3
$\frac{dm}{dt}=\frac{\left(V^2 / R\right)}{L}=\frac{(210)^2 / 20}{80 \times 4.18}$ = 6.59 gs-1