Question

The temperature of water at the surface of the lake is\[ - {20^0}C\]. Then find the temperature of the water just below the lower surface of the ice layer.
A. \[ - {4^0}C\]
B. \[{0^0}C\]
C. \[{4^0}C\]
D. \[ - {20^0}C\]

Answer 1

Hint: We know that water exists in three states- solid, liquid, and gas. The solid form is known as ice and the gaseous form is water vapor. when a certain temperature is attained the change of state takes place. When the state changes, the temperature of the system will not change and this unique property plays a very important role in the existence of life on this planet.

Complete step by step solution:
Here, we have a lake. The temperature of the water surface of the lake is \[ - {20^0}C\]. Let us say some of the portions below the water surface are converted into ice. We know that the density of water is maximum \[{4^0}C\]. So, the temperature of the water at the bottom of the lake is \[{4^0}C\].

As you move up temperature goes on and decreases and, on the layer, just below the ice the temperature will be \[{0^0}C\]. Then if you go further up the temperature further decreases and, on the surface, we know that the temperature is \[{20^0}C\]. Therefore, the temperature just below the ice layer is \[{0^0}C\].

Hence, option C is the correct answer.

Note: Here in the given problem we can say that the temperature of the water at the surface of the lake is very less and since at lower temperatures water gets converted into ice as discussed above.