Very short answer type Section B

Very Short Answer Questions – Atmospheric Pressure

1. Write the numerical value of atmospheric pressure on the surface of the Earth in pascal.

1.013 × 10⁵ pascal

2. What physical quantity is measured in torr? How is it related to the S.I. unit of the quantity?

Pressure; 1 torr = 133.3 pascal

3. Name the physical quantity which is expressed in the unit 'atm'. State its value in pascal.

Pressure; 1 atm = 1.013 × 10⁵ pascal

4. A partially inflated balloon is placed inside a bell jar connected to a vacuum pump. On creating vacuum inside the bell jar, the balloon gets more inflated. How does the pressure change inside the:
(a) bell jar
(b) balloon?

(a) Decrease     (b) Decrease

5. What is the purpose of a barometer?

To measure atmospheric pressure

6. What is meant by the statement "the atmospheric pressure at a place is 76 cm of Hg"? State its value in pascal.

It means the pressure is 1.013 × 10⁵ pascal

7. How is the barometric height of a simple barometer affected if:
(a) its tube is pushed down into the trough of mercury?
(b) its tube is slightly tilted from vertical?
(c) a drop of liquid is inserted inside the tube?

(a) Remains unaffected
(b) Remains unaffected
(c) Decreases

8. State two uses of a barometer.

1. Measuring atmospheric pressure
2. Predicting weather changes

9. How is the height of mercury in a barometer affected when it is taken to:
(i) a mine, and (ii) a hill?

(i) Increases     (ii) Decreases

10. 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

(a) Possibility of Rain
(b) Storm or cyclone
(c) possibility of dry weather