Measurement of Atmospheric Pressure

Q. The density of the material in CGS system of units is 4g/cm3. In a system of units in which unit of lenght is 10 cm and unit of mass is 100g , the value of density of material will be

Q. The measure of mass and volume of a body are 2.00g and 5.0cm3respectively, with possible errors of 0.01g and 0.1cm3. What would be the maximum permissible error in its density?

Q. A block of wood is kept on a table top.The mass of wooden block is 5kg and it's dimensions are 40cm×20cm×10cm.Find the pressure exerted by the wooden block on the table top if it is made to lie of dimensions (a)20cm×10cm (b) 40cm×20cm

Q.

A manometer is used to measure atmospheric pressure

1. True
2. False

Q.

Why is mercury used in a barometer?

1. The density of mercury is high as compared to other fluids.

2. The density of mercury is less as compared to other fluids.

3. Mercury flows easily.

4. Changes in mercury level are easier to detect.

Q.

Give two reasons why water is not a suitable barometric liquid.

Q.

What is an aneroid barometer ? Draw a neat and labelled diagram to explain its construction and working.

Q.

Density of mercury is more than that of water.

1. True

2. False

Q.

What do the following indicate in a barometer regarding weather :
(a) gradual fall in the mercury level,
(b) sudden fall in the mercury level,
(c) gradual rise in the mercury level ?

Q.

State two advantages of an aneroid barometer over a simple barometer.

Q. what volume of silver metal will weigh exactly 2500g. the density of silver is 10.5g/cm^3

Q.

Gauge pressure is measured with which of the below instruments?

1. Manometer

2. Barometer

3. Hydrometer

4. Thermometer

Q.

Mention two demerits of a simple barometer and state how they are removed in a Fortin barometer.

Q.

What will happen if there are air bubbles are introduced into the barometer tube?

1. The mercury in the tube will react violently with the air.

2. The height of the mercury column will increase.

3. The height of the mercury column will decrease.

4. The height of the mercury column will remain the same.

Q.

Give two reasons for the use of mercury as a barometric liquid.

Q.

How will you show that there is vacuum above the surface of mercury in a barometer? What name is given to this vacuum?

Q.

A manometer measures the atmospheric pressure.

1. True
2. False

Q.

The density of copper is 9 g/cm³. Then the volume of 90 g copper is

1. 810 cm³

2. 9 cm³

3. 10 cm³

4. 90 cm³

Q.

State two uses of a barometer.

Q.

Why is the barometric height used as a unit to express the atmosphric pressure ?

Q.

What is the purpose of a barometer ?

Q.

To observe and compare the pressure exerted by three different faces of a cuboid on sand, the following Cuboid is available to you:

(A) Wooden cuboid of dimension 20 cm x 30 cm x 50 cm

(B) Aluminium cuboid of dimension 3 cm x 6 cm x 12 cm

(C) Iron cuboid of dimension 5 cm x 10 cm x 50 cm

(D) Iron cuboid of dimension 20 cm x 30 cm x 15 cm

The best choice from the practical point of view would be:

1. C

2. B

3. A

4. D

Q.

How can we determine the weather condition with decrease or increase in level of mercury of simple barometer

Q.

The unit torr is related to the barometric height as

(a) 1 torr = 1 cm of Hg

(b) 1 torr = 0.76 m of Hg
(c) 1 torr = 1 mm of Hg

(d) 1 torr = 1 m of Hg

Q.

The mass of water displaced by a solid of mass 400 g and volume 150 cm³ is

1. 150 cm³

2. 400 g

3. 250 g

4. 150 g

Q. What happens to the height of barometer when atmospheric pressure drops?
$h=$ Height of liquid in barometer.

1. $h$ increases.
2. $h$ decreases.
3. $h$ does not change.
4. $h$ becomes zero.

Q. R.D. Of Mercury is 13.6. Three density of water is 10³kg/me. What is three density of Mercury in SI unit?

Q.

The pressure caused by a column of liquid is calculated using the equation___

1. p = $\frac{\rho h}{g}$

2. p = ρgh

3. p = ρgm

4. p = $\frac{\rho g}{h}$

Q.

Barometers can be used for which of the following purposes?

1. To measure height.

2. All of the above

3. Weather forecasting.

4. To measure atmospheric pressure.

Q. Water is not used as a barometric liquid because

1. it is difficult to have a barometer tube 11 m long.
2. water vaporises under vacuum conditions.
3. all the above
4. water sticks to the side of glass tube.