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If a wire of resistance 20 \Omega is covered with ice and a voltage of 210 V is applied across the wire, then the rate of melting of ice is

Option: 1

8.85 \mathrm{gs}^{-1}


Option: 2

1.92 \mathrm{gs}^{-1}


Option: 3

6.56 \mathrm{gs}^{-1}


Option: 4

None of these


Answers (1)

best_answer

The rate of heat developed is given by

\mathrm{\frac{V^2}{R}=\frac{(210)^2}{20}=2205 \mathrm{Js}^{-1}=\frac{2205}{4.2} \mathrm{cals}^{-1} }

Let m be the amount of ice melting per sec and, then

\mathrm{m \times 80=\frac{2205}{4.2} \text { or } m=6.56 \mathrm{gs}^{-1} }

Posted by

Ritika Kankaria

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