1. (a) what name is given to the law describing the relationship between volume and pressure at constant temperature? write a mathematical expression that describes this relationship. (2 marks)
(b) sketch a graph of the relationship described in part (a).

Explanation:

a) Boyle's law states that pressure is inversely proportional to the volume of the gas at constant temperature.  

(At constant temperature)

The equation given by this law is:

where,

are initial pressure and volume respectively.

are final pressure and volume respectively.

b) A graph of the relationship is attached as an image.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.