A balloon with hydrogen in it rises up

cbse
mechanical-fluids

#1

A balloon with hydrogen in it rises up but a balloon with air comes down. Why?


#2

The density of hydrogen is less than air. So, the buoyant force on the balloon will be more than its weight in case of the hydrogen. So in this case the balloon rises up. In case of air, the weight of balloon is more than the buoyant force acting on so it will come down.