Question

An egg sinks when immersed in water contained in a vessel. On dissolving a lot of salt in the water, the egg will:
A. Develop cracks in the shell
B. Break
C. Rise and then float
D. Remain where it is

Answer 1

First of all, we will take into account the fluid displaced by the egg when it is dipped in it. The weight lost by the egg is equal to the fluid displaced.

Complete step by step answer:
In the given question, we are supplied the following data:
There is an egg which when placed in plain water, it sinks.
We are asked to find out what will happen to the egg, if we dissolve a lot of salt in the water.

To begin with,
We bring the Archimedes principle, which notes that the upward buoyant force applied on a body immersed in a fluid is proportional to the weight of the fluid that the body displaces, whether completely or partly submerged. The theory of Archimedes is a law of physics which is essential to the dynamics of fluids.
Here in the case of the egg, as you all know, the weight of the egg acts vertically downwards while at the same time the water provides an upward thrust to the test tube to balance in its position. This upward thrust is called buoyant force.
In the first case, the egg fully sinks down the vessel containing the water, as the weight of the egg is more than the buoyant force exerted by the liquid on the egg. The net resultant force is along the downward direction. The density of plain water is $1\,{\text{gc}}{{\text{m}}^{ - 3}}$ .
But, in the second case, we have added a lot of salt, as a result of which the density of the water will now increase. However, the density of saltwater is $1.1\,{\text{gc}}{{\text{m}}^{ - 3}}$ .
We can now conclude that, higher is the density of the fluid, less is the fluid displaced or vice-versa.
The egg will rise up and then float.

So, the correct answer is “Option C”.

Note:
To answer this question, we must have the theoretical knowledge of the Archimedes principle. Many students seem to make mistakes by taking into account that, more the fluid displaced, higher is the density, which is wrong. A ship dips less in marine water than in freshwater, as the density of marine water is more than that of fresh water.