Choose the correct statements from the following

Options

A. A body will sink in a liquid if its weight is equal to or greater than the weight of the liquid displaced by it.
B. A body will float in a liquid if its weight is equal to or less than the weight of liquid displaced by it.
C. When a body floats in a liquid, the portion of the body above the surface of the liquid is independent of the density of the body relative to that of the liquid.
D. In still air, a hydrogen filled balloon rises up to a certain height and then stops rising.

Answer

B, D

Explanation

The option a is incorrect. A body will sink if its weight is greater than the upthrust. Option b is correct. Option c is incorrect. Option d is correct. The density of hydrogen is less than that of air. Therefore, initially, the balloon rises because the upthrust due to air is greater than the weight of the hydrogen filled balloon. The density of air decreases, as we go up. Therefore, the upthrust on the balloon also decreases. It will stop rising when it attains a height at which the upthrust becomes equal to its own weight.