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Grade 11Mechanics

A simple U-tube contains mercury. When 11.2 cm of water is poured into the right ann, how high does the mercury rise in the left arm from its initial level ?

Profile image of Simran Bhatia
11 Years agoGrade 11
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2 Answers

Profile image of Aditi Chauhan
11 Years ago

When 11.2 cm of water is poured into the right arm of a simple U-tube containing mercury, the mercury will rise in the left arm. To find out how high the mercury rises in the left arm, we can use the concept of pressure and the properties of fluids.

Understanding Pressure in a U-tube

In a U-tube, the pressure at any point in a fluid is the same horizontally. This means that the pressure at the same height on both sides of the U-tube is equal.

Solving for the Height of Mercury

When the water is poured into the right arm, the pressure at the same height in both arms must be equal. We can use the following formula to calculate the height of the mercury in the left arm:

Pwater = Pmercury

Since pressure is given by the formula P = ρgh (where ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height), we can set up the equation as follows:

ρwaterg(11.2) = ρmercuryg(h)

h = (ρwatermercury) * 11.2

Calculating the Height

Mercury is much denser than water, so the density of mercury (ρmercury) is greater than the density of water (ρwater). Therefore, the height of the mercury in the left arm will be less than 11.2 cm.

By substituting the values for the densities of water and mercury (ρwater = 1000 kg/m3, ρmercury = 13600 kg/m3) into the equation, we can calculate the height at which the mercury rises in the left arm.

Conclusion

By solving the equation, you can find out how high the mercury rises in the left arm of the U-tube when 11.2 cm of water is poured into the right arm. This demonstrates the principles of fluid pressure and density in action.

Profile image of ankit singh
5 Years ago
When water is added to one side of the U tube, the rise in mercury level of the other side of the U tube will be depend on the density of water and mercury.
The height of water added in one arm = 13.6cm, we have to calculate the corresponding rise in level in the other arm
The pressure difference tn the two arms will be equal
So, the pressure difference in water column = the pressure difference in the other arm or mercury
                     i.e. hHg d g  = hW d g
                          hHg    = hW×density of water × g ÷ density of mercury × g
                                  = 13.6cm × 1000kg/m3 × g ÷ 13.6 × 1000kg/m3 × g
                                  = 1cm
i.e. When 13.6cm water is added to one arm of the U tube, only a height of 1cm will be the rise in mercury level in the other arm