# Conversion Factor

1. Apr 15, 2009

### questions_uk

I have a list of readings in mV and it says "The metre readings have a conversion factor of 9.29 V/J.

If there is a reading of 10 mV would you just do 10/9.29 to convert to Joules?

Thanks.

2. Apr 15, 2009

### whybother

10mV is in miliVolts, or 10mV = (10/1000) V

So to convert 10mV into, let's call it Unit J (instead of Joules for a minute) (instead of mJ), using the given conversion, mathematically it's:

$$10mV = {{10mV \over 1000{mV \over V}} \over 9.29 {V \over J}}$$

(writing it out that way with is just to maybe help you see how the units work)

EDIT: But as an important note... Volts aren't the same as Joules
A Joule is a unit of energy, and 1 Volt is equal to 1 Joule of energy per Coulomb of charge, so V = J/C, in general. You can't convert from Volts to Joules, but you can convert from V to J/C, which is what I assume you are really doing, and the 9.29 has some unit related to charge.

Last edited: Apr 15, 2009