Question

Describe about absolute pressure gauge pressure and atmospheric pressure

Answer 1

Absolute pressure is zero referenced against a perfect vacuum,so it is equal to gauge pressure plus atmospheric pressure.
Gauge pressure is zero referenced against ambient air pressure,so it is equal to absolute pressure minus atmospheric pressure.
Atmospheric pressure is applied pressure applied by the air

Answer 2

The simplest way to explain the difference between the two is that absolute pressure uses absolute zero as its zero point, while gauge pressure uses atmospheric pressure as its zero point. Due to varying atmospheric pressure, gauge pressure measurement is not precise, while absolute pressure is always definite