Question

Mercury is used in barometer because of its _____
1. High boiling point
2. Low melting point
3. High melting point
4. High density

Answer 1

Correct Answer - Option 4 : High density

CONCEPT:

• Atmospheric Pressure: The pressure exerted by gasses present in the atmosphere on the earth's surface is called atmospheric pressure.
• Mercury Barometer: It is a device used to measure atmospheric pressure.
• Working of Mercury Barometer: 
  • The set up is made according to the above diagram.
  • The barometer basically consists of a mercury reservoir and an inverted tube full of mercury. 
  • It is based on the principle that equal pressure is applied at the same height in a fluid.
  • If the pressure exerted by mercury in the tube is less than the atmospheric pressure, the mercury level in the tube will rise to make its pressure equal to atmospheric pressure.
  • If the pressure exerted by mercury in the tube is more than atmospheric pressure, it will have reduced to a lower level to maintain the pressure.
  • Mercury is liquid having high density. Its expansion in tube will not be much high for very high-pressure variations.
  • In this way, it could be managed in a small tube

EXPLANATION:

• So, a mercury barometer is a device used to measure atmospheric pressure and mercury is used in it because of its high density.
• So, High density is the correct answer