Suppose a little bubble of air has gotten into the top of a mercury barometer. If a person uses a barometer in the usual way, the reading of atmospheric pressure will be
A) correct.
B) higher than the actual value.
C) lower than the actual value.

Question

Quizplus · Accepted Answer

The presence of an air bubble in the mercury column of a barometer will cause the mercury level to be lower than it should be for a given atmospheric pressure, because the bubble will take up some space at the top and prevent the mercury from rising as high as it would without the bubble. This results in a reading that is lower than the actual atmospheric pressure.

Suppose a Little Bubble of Air Has Gotten into the Top