Variation of Atmospheric Pressure with Altitude.

Q.

What is atmospheric pressure? Write any four applications of atmospheric pressure.

Q.

A simple U tube contains mercury to the same level in both of its arms. If water is poured to a height of 13.6 cm in one arm, how much will be the rise in mercury level in other arm? Density of mercury $13.6\times {10}^{3}kg/m^3$ and density of water = $1000kg/m^3$.

Q.

The gravitational force between two objects is F. If the masses of both objects are doubled and the distance between them is also doubled, then the gravitational force would become

1. F/4

2. 4F

3. F

4. 16F

Q.

Explain how submarines float and sink?

Q.

Why does a fountain pen leak at a high altitude ?

Q.

State two factors on which the gravitational force between two objects depends.

Q.

State two factors which affect the atmospheric pressure as we go up.

Q.

Who gave the universal law of gravitation?

Q.

Which of the following graph correctly shows the variation of atmospheric pressure with altitude?

1. 

2. 

3. 

4. 

Q.

What is an altimeter ? State its principle. How is it's scale calibrated ?

Q.

Water flows through the tube shown in figure. The areas of cross section of the wide and the narrow portions of the tube are 5 cm² and 2 cm² respectively. The rate of flow of water through the tube is 500 cm³ s^-1. Find the difference of mercury levels in the U-tube. Assume this tube lying horizontally on a table.

1. 1.93 cm

2. 1.93 m

3. 2.58 m

4. 2.58 cm

Q.

Why does nose start bleeding on high mountains ?

Q.

What do you mean by gravitation?

Q.

What is the effect of height on barometric pressure? Explain your answer by drawing a graph.

Q. Classify tension force in the string as contact force or non-contact force.

Q.

In high air pressure, the molecules are

1. hot and moving rapidly

2. warm and moving slow

3. close together and moving slowly

4. far apart and moving fast

Q.

The liquids shown in figure in the two arms are mercury (specific gravity = 13.6) and water. if the difference of heights of the mercury columns is 2 cm, find the height h of the water column.

1. 0.27 cm

2. 27 cm

3. 27 dm

4. 2 mm

Q.

Which scientist experimentally measured the value of G?

Q.

How can submarines and whales sink and rise to the water surface at their own will?

Q.

The centripetal force required for the revolution of a planet around the sun is provided by the gravitational force acting on the planet due to the sun.

1. True
2. False

Q.

Name the property of attraction between any two objects.

Q.

Calculate the pressure exerted by 0.8 m vertical length of alcohol of density 0.80 g cm^-3 in SI units. (Take g=10 m/s)

Q.

If the density of a liquid is 20 g cm^-3, height is 4 cm and the gravitational field strength is 10 N kg^-1, the pressure at the bottom of the liquid is

1. 8 Pascal

2. 50 Pascal

3. 8000 Pascal

4. 2 Pascal

Q.

How is a barometer used as an altimeter?

Q.

An aneroid barometer can be used as an altimeter.

1. True
2. False

Q.

The force of a freely falling body is directly proportional to :

1. mass of the body

2. acceleration of the body

3. velocity of body

4. both (a) and (b)

Q. Calculate the pressure due to a water column of height 120 m. (Take $g=10m{s}^{-2}$ and density of water $=103kg{m}^{-3}$)

1. $5\times {10}^{5}N{m}^{-2}$
2. $12\times {10}^{5}N{m}^{-2}$
3. $10\times {10}^{5}N{m}^{-2}$
4. $12\times {10}^{5}Pa$

Q.

It is said that the mass of an object remains constant at all places while the weight may change. Why?

Q. Explain why an iron needle sinks in water, but a ship made of iron floats on water.

Q.

Amount of pressure of liquid increases with

1. volume

2. base area

3. depth

4. mass