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
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
[Latent heat of ice is 3.4 × 105 J/kg and g = 10 N/kg]
(A) 136 km
(B) 68 km
(C) 34 km
(D) 544 km
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(A) 136 km
When the piece of ice falls from the height h, it possesses potential energy, mgh.
This P.E. is converted to heat energy.
∴ Q = mgh
But only \(\frac{1^{th}}{4}\) of it is absorbed by ice which is used to change the state.
∴ \(\frac{mgh}{4}\) = mL
∴ \(\frac{10\times h}{4}\) = 3.4 × 105
∴ h = 13.6 × 104 m = 136 km
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