A hollow glass sphere is balanced by counterpoising weights made of brass in a common balance. The whole system is then covered with an air-tight bell jar and the jar is evacuated. What will be the result?

A hollow glass sphere is balanced by counterpoising weights made of br

1.	A hollow glass sphere is balanced by counterpoising weights made of brass in a common balance. The whole system is then covered with an air-tight bell jar and the jar is evacuated. What will be the result?
Answer» Solution :Since the density of glass is LESS than the density of brass, the volume of the glass sphere is GREATER than the volume of the same mass of brass weights. So, in air, the glass sphere experiences a larger buoyant FORCE than the brass weights. Now, when the bell jar is evacuated, this buoyant force ceases to act hence the weight of the glass sphere becomes more than that of the brass weights. Hence, the end of the BALANCE beam containing the glass sphere will move downwards.