Question

If the pressure today is 30.03, what is it in mmHg and in atm?

Answer 1

We talking inches of mercury? So much for the metric system. Mind you, now that Blighty is leaving the EU, we might readopt pounds, shillings, and pence....I will have to practise...20 shillings per pound, and 21 shilling to the guinea. What!

Explanation:

Now as far as I know `1*"inch"=25.4*mm`...

And since the mercury measurement of pressure is PURELY a linear measurement of how high the atmosphere pushes up the mercury column...and so...

`30.03*"inches"xx25.4*mm*"inch"^-1=762.8*mm`

And since `1*atm-=760*mm*Hg`...we gots...

`(762.8*mm)/(760*mm*atm^-1)=1.004*atm`

Note that you use a mercury column for measurement of pressure at ABOUT 1 atmosphere or lower. If you are quoted a measurement of say `1*m` of mercury you know it is non-kosher.