Question

Which of the following is NOT an example of heat transfer predominantly through radiation?​

• A. Basking by the fire​
  
• B. Getting heat from the Sun​
• C. Heating the air inside a hot air balloon
• D. Drying clothes using sunlight​

Answer 1

The correct option is C Heating the air inside a hot air balloon

We know that the predominant mode of heat transfer is conduction for solids. For fluids convection is predominant. Radiation does not require any medium. A hot body radiates heat in all directions.

Let’s see them one by one.

Getting heat from the sun: Sun is a really very hot body. It radiates heat in all directions and heat from the sun reaches us by radiation. Therefore, receiving heat from the Sun and drying clothes using sunlight, these examples are strongly associated with radiation.

Heating the air inside the hot air balloon: In hot air balloons the burner inside the balloon heats up the air and the warmer air moves upward. This trapping of hot air inside causes the balloon to rise. So, the air inside the balloon is heated by convection.

Basking by the fire: In this process radiation as well as convection is involved. Fire radiates heat in all directions but at the top of the fire convection also takes place.