Question

The snow on mountain does not melt all at once when it is heated by the sun because it
(A) Becomes very hard
(B) Reflects most of the heat from the sun
(C) Has a low specific heat capacity
(D) Has a high latent heat of fusion

Answer 1

Hint: The heat received from the sun increases the temperature from negative to zero. At zero degrees the snow changes from solid to liquid state and the energy required for this change is called latent heat. Since this latent is very high it requires more heat and time therefore the ice does not melt all at once.

Complete Step by step solution
The snow on mountains is basically ice. It is at some negative temperature (in Celsius). When the snow on the mountains starts receiving heat energy from the sun, its temperature starts rising to a less negative value and approaches $0^\circ C$ . After reaching the melting point, i.e. $0^\circ C$ , the heat energy that the snow is receiving from the sun starts getting used up in changing the state from solid to liquid. This heat energy required to change the state of a substance from solid to liquid is termed as latent heat of fusion. Since, the latent heat of fusion is very high for ice, it takes more heat and time to melt. Had the latent heat of ice been low, all the snow would have melted all at once.

Therefore, option (D) is correct.

Note: The specific latent heat of fusion of ice/snow is 336000 Joules per kg or 336 Kilo Joules per kg. This causes the conversion of snow into water to be a slow process.