Thermal Properties of Matter - Result Question 15
15. A piece of ice falls from a height $h$ so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of $h$ is :
[2016]
[Latent heat of ice is $3.4 \times 10^{5} J / kg$ and $g=10 N /$ $kg]$
(a) $34 km$
(b) $544 km$
(c) $136 km$
(d) $68 km$
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Answer:
Correct Answer: 15. (c)
Solution:
- (c) According to question only one-quarter of the heat produced by falling piece of ice is absorbed in the melting of ice.
i.e., $\frac{mgh}{4}=mL$
$\Rightarrow h=\frac{4 L}{g}=\frac{4 \times 3.4 \times 10^{5}}{10}=136 km$.