Question

Mercury boils at 367$^{\circ}$C. However, mercury thermometers are made such that they can measure temperature upto 500$^{\circ}$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 oxygen gas at high pressure above the mercury column
• D. filling nitrogen gas at low pressure above the mercury column

Answer 1

Answer: (B)

filling nitrogen gas at high pressure above the mercury column

Answer 2

If we fill nitrogen gas at high pressure above mercury level, the boiling point of mercury is increased which can extend the range upto 500$^{\circ}$C.