Which of the following statements about heat transfer is/are incorrect?

In radiation, energy passes from one body to another without changing the medium in between.
Radiation and convection can take place in vacuum, whereas conduction needs a material medium.
Conduction can occur in solids, while convection takes place in liquids and gases.
All of the above statements are correct.

Correct answer: Radiation and convection can take place in vacuum, whereas conduction needs a material medium.

Solution

The question asks which statement is incorrect. Statement (b) claims radiation AND convection can occur in vacuum, but convection requires a material medium and cannot happen in vacuum, so (b) (index 1) is the incorrect statement.

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