# Light source

1. Nov 14, 2007

### pardesi

what do we mean when we say a point light source is $$5.0 mW$$

Last edited: Nov 14, 2007
2. Nov 14, 2007

### mgb_phys

That is an energy - so not very useful, unless it means 5.0mJ/s ie 5milliWatts.

In astronomy it could be a typo for mJy = milli Jansky bit this isn't commonly used for visible light

Last edited: Nov 15, 2007
3. Nov 14, 2007

### pardesi

sorry that was watt.

4. Nov 15, 2007

### Shooting Star

It's not energy, it's power. It means the light source is giving out energy at the rate of 5 J/s.