Question

A vacuum gage connected to a chamber reads 39 kPa at a location where the atmospheric pressure is 92 kPa. Determine the absolute pressure in the chamber?

Answer 1

Answer: 53 kPa

Explanation:

Absolute pressure is a pressure value referred to absolute zero or vacuum. This value indicates the total pressure to which a body or system (the chamber in this situation) is subjected, considering the total pressure acting on it.

In this sense, the equation that will be useful in this case is:

$P_{atmospheric}= P_{absolute} + P_{vacuum}$  (1)

Where:

$P_{atmospheric}=92 kPa$ is the atmospheric pressure

$P_{vacuum}=39 kPa$ is the vacuum pressure

$P_{absolute}$ is the absolute pressure

Isolating $P_{absolute}$  from (1):

$P_{absolute}=P_{atmospheric} - P_{vacuum}$  (2)

$P_{absolute}=92 kPa - 39 kPa$  (3)

Finally:

$P_{absolute}=53 kPa=53(10)^{3} Pa$ This is the absolute pressure in the chamber