Q428
A barometer is kept inside a bell jar. Air is slowly pumped out of the jar.
A.
The mercury level starts rising
AnswerB.
The mercury level starts falling
C.
The mercury level does not change
D.
The bell jar breaks up
Answer: Option A
Solution
Answer: Option A
Solution:
As the pump removes the air from the bell jar the pressure obviously reduces around the barometer. The reduction in pressure around the barometer leads it to expand. As the pump removes air from the jar, the mercury level rises.