Question

Mercury boils at 367°C. However, mercury thermometers are made such that they can measure temperature up to 500°C. This is done by

• A. Maintaining vacuum above mercury column in the stem of the thermometer
• B. Filling nitrogen gas at high pressure above the mercury column
• C. Filling nitrogen gas at low pressure above the mercury level
• D. Filling oxygen gas at high pressure above the mercury column

Answer 1

Answer: (B)

Filling nitrogen gas at high pressure above the mercury column

Answer 2

By filling nitrogen gas at high pressure, the boiling point of mercury is increased which extend the range upto 500°C.