Question

Give the reason
a A balloon filled with hydrogen rises in air b it is easier to swim in Sea water than in River water

Answer 1

Answer:

A) When the balloon is filled with hydrogen gas, the density of the balloon becomes less than the density of the atmospheric air. The weight of the balloon becomes less than the upthrust or buoyant force acting on it. Hence, the balloon floats in the air.

B) It is because sea water contains more amount of salt as compared to river/fresh water as a result its density increases and hence it easier to swim in sea water.

Hope it helps!!