Question

Heat is being supplied at a constant rate to the sphere of ice which is melting at the rate of $0.1gm/s$. If melts completely in $100s$. The rate of rise of temperature thereafter will be:

• A. ${0.4}^{o}C/s$
• B. ${2.1}^{o}C/s$
• C. ${3.2}^{o}C/s$
• D. ${0.8}^{o}C/s$

Answer 1

The correct option is D ${0.8}^{o}C/s$

According to rate of heat flow relation.

$\frac{dQ}{dt}=\frac{dM}{dt}L\Rightarrow \frac{dQ}{dt}=0.1\times 334J/s\Rightarrow \frac{dQ}{dt}=33.4J/s$

Because we know that

$\because \frac{dQ}{dt}=MS\frac{dT}{dt}=33.4J/s\Rightarrow \frac{dT}{dt}=\frac{33.4}{0.01\times 4200}=0.795K/s\approx 0.8K/s$