Question

Why does hot air move upwards and cold air move downwards?

a) Because hot air is heavier than cold air. B) Because hot air is lighter than cold air. C) Because hot air is denser than cold air. D) Because hot air has less heat than cold air

Answer 1

(B) hot air is lighter than cold air

P V = N R T ideal gas equation

If T (temperature) is smaller then N (number of moles) must be larger if other quantities remain constant,