Use this graph to help you answer the following questions. The variable 'I' means flux.

1. Suppose the luminosity of a star called Alpha is 100 Luminosity units and if located a distance r away, has a measureable flux of 1000 flux units. What is the flux of Alpha if it is located twice this ditance? 5 times this distance? 10 times this distance away?

2. Suppose another star Beta has exactly twice the luminosity of Alpha. What is this luminosity in luminosity units? What is the flux of Beta at r? What is the flux at 5 times this distance? 10 times this distance away?

3. Now for this problem, Alpha is indeed located 2r away from Earth. You measure the flux of another star called Gamma. It has the same flux as Alpha, but from other measurements, you realize that Gamma's luminosity is 4 times greater than Alpha. Firstly, what is the flux of Gamma? how far away is this star from Earth in units of r?
   If you are stuck, this simulation may help you as well lightdetector.

   Set one bulb on 400 watts and one on 100 watts. See how far you must move away from the 400 watt bulb to have the same flux as 100 watt bulb. This is subtle, so try the 100 watt bulb at 1 and then try it at 2.

4. The star Delta is located at 10r and has a flux of 200 flux units, what Delta's luminosity?