NCERT Class 11 Physics Solutions: Chapter 10 – Mechanical Properties of Fluids-Part 5 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 10.9:

A U-tube contains water and methylated spirit separated by mercury. The mercury columns in the two arms are in level with of water in one arm and of spirit in the other. What is the specific gravity of spirit?

Answer:

The given system of water, mercury, and methylated spirit is shown as follows:

Height of the spirit column,

Height of the water column,

Atmospheric pressure

Density of spirit

Density of water

Pressure at point

Pressure at point

Pressure at points is the same.

Therefore, the specific gravity of spirit is

Question 10.10:

In problem , if of water and spirit each are further poured into the respective arms of the tube, what is the difference in the levels of mercury in the two arms? (Specific gravity of mercury

Answer:

Height of the water column,

Height of the spirit column,

Density of water,

Density of spirit,

Density of mercury

Let be the difference between the levels of mercury in the two arms.

Pressure exerted by height , of the mercury column:

Difference between the pressures exerted by water and spirit:

Equating equations we get:

Hence, the difference between the levels of mercury in the two arms is

Question 10.11:

Can Bernoulli՚s equation be used to describe the flow of water through a rapid in a river? Explain.

Answer: No

Explanation:

Bernoulli՚s equation cannot be used to describe the flow of water through a rapid in a river because of the turbulent flow of water. This principle can only be applied to a streamline flow.