Question

A specific gravity bottle weighs 21.2 gm when empty and 46.2 gm when filled with water at 4 degree Celsius the capacity of the bottle is:
A).25cc
B).50cc
C).30cc
D).40cc

Answer 1

Hint: In this question we will use the basic concept that the density of water is 1g/ml at 4 degree Celsius. This will directly give us the required result. Further we will understand what are the changes taking place when we put a weight in a liquid.

Complete answer:
Here, weight of water is given by:
$46.2 - 21.2 = 25g$
Now, at 4 degree Celsius, the density of water is 1g/ml
So, at 25g of water the capacity of the bottle will be 25ml.

Therefore, the correct option is A) i.e., the capacity of the bottle is 25cc.

Additional information:
We should know about the buoyant force. This is an upward force exerted by a fluid which opposes the weight of a partially or fully immersed object in the fluid. Here, in the fluid, pressure increases with depth as a result of the weight of the overlying fluid. So, the pressure at the bottom of a column of fluid is greater than at the top of the column.
 Archimedes principle states that an object immersed in a fluid experiences some buoyant force that is equal in magnitude to the force of gravity on the displaced fluid. It is also known as the law of buoyancy.
The weight of the displaced fluid is equal to the subtraction of weight of object in vacuum and weight of object in fluid. The weight of the displaced fluid is directly proportional to the volume of the displaced fluid (if the surrounding fluid is of uniform density).The buoyant force on a body floating in a liquid or gas is also equivalent in magnitude to the weight of the floating object and is opposite in direction. So, in this situation the object neither rises nor sinks.

Note:
One should notice that the Archimedes principle is only valid for fluids, where buoyant force can be observed. Also, the displaced fluid is equal to the weight of the object immersed in the water. In the displaced fluid, gravity also plays an important role.