# Gauge pressure

1. Apr 18, 2012

### kimkibun

good day!

i was asked to solve for gauge pressure, pg1, using the combined Boyle's and Charle's Law,

(pg1V1)T1=(pg2V2)T2

where V is the volume of gas and T is the temperature (in °C). now here's my question, we know that in computing for absolute pressure we need to convert the temperature to Kelvin (or Rankine) if the given is in °C, since gauge pressure is the difference between the absolute and atmospheric pressure, do i need to convert the given temperature in °K?

thanks and GB!

2. Apr 18, 2012

### Psi^2

Yes, you need, because Boyle's and Charle's Law are derived form ideal gas formula (pV=nRT=NkT) where temperatures are given in Kelvins. If you put Celsius you will have different dimensions.