Question

Morning sun is not so hot as the midday sun because:
A. sun is cooler in the morning
B. heat rays travel slowly in the morning
C. it is a god gift
D. the sun’s rays travel a longer distance through the atmosphere in the morning.

Answer 1

Hint: Heat transfer occurs from hot body to the cold body. Generally, it happens through three ways which can be through conduction and convection and radiation. This question is related to heat transfer.

Complete step-by-step solution:
Conduction generally happens in solids. Convection occurs in fluids. These two processes require the medium to propagate the heat. While radiation doesn’t require any medium.
When we place a hot rod in contact with another rod whose temperature is less than the previous hot rod temperature, then heat will transfer to the relatively cold rod through conduction. Conduction is nothing but the heat will be carried to adjacent molecules through vibration. Energized molecules don’t go anywhere they just vibrate. We can relate this to the dominos effect.
When we boil the water then water in contact with the stove gets heated first and its density decreases and up and molecules from the top come down and get heated. This process is called convection and it happens due to variation in densities during heating.
Now coming to the radiation we feel the heat due to the sun but in space, no atmosphere is present and the only vacuum is present. In this case heat transfers through radiation.
In all the three cases the more distance heat travels the more energy is lost due to thermal resistance.
So during the morning sun will be on the horizon and rays should travel longer distances so more heat is lost and during midday sun is on our heads and rays will travel very less distance so less heat is lost. Hence we feel more heat during midday than in the morning.
Hence option D will be correct.

Note: Sun is the ideal source of heat which means it is the heat reservoir. It is considered as a black body because it absorbs all kinds of radiation and its emissivity is also very high. The more heat is lost the cooler we feel.