Apile of wet mud and a pile of sandy clay are placed next to each other on a sunny day. if the temperature of each pile is equal and allowed to cool in the shade for a few minutes, which substance is likely to show a lower temperature and why? a. wet mud, because it released more heat while placed in the sun. b. sandy clay, because it absorbed more heat while placed in the sun. c. wet mud, because it requires less energy to increase its temperature. d. sandy clay, because it needs to release less energy to decrease its temperature.

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.