Question

Which of the following example explain convection?

(a) The heat from a hot liquid makes the cup itself hot

(b) Walking on the beach on a hot summer day will warm the feet

(c) A metal spoon becomes hot from the boiling water inside the pot

(d) The formation of sea and land breeze

I had been asked this question in final exam.

I want to ask this question from Heat Convection in section Heat Transfer Theory of Food Processing Unit Operations

Answer 1

Right answer is (d) The formation of sea and land breeze

Easiest explanation: The formation of sea and land breeze is an example of convection. During a day, the sun the sun warms the ground and sea water. Since the ground has lower specific heat compared to water and so its temperature increases more than the temperature of the water. The air above ground is heated thus forming a rise in the convection currents and the cool air from over sea flows towards shore. This is called as sea breeze. Similarly in the evening, ground cools faster than water and therefore breeze flows from shore to sea.