Calculating Luminosity (Easy Atronomy Question)

[zoiberg137]

Capella is the same temperature as our sun, but about ten times the suns diamter; it must be about_____ times as luminous as our star.

Could someone please tell me how to solve this type of problem??

I am aware of the formula R=sqrt(L)/Temp squared.

But I'm not sure how to apply that here. Inserting my own made up radius of 2 for the sun and 20 for Capella, I come up with the answer being "100 times as luminous". But I fee like I am missing something...

Thanks!

 

[tiny-tim]

hi zoiberg137!

I am aware of the formula R=sqrt(L)/Temp squared.

But I'm not sure how to apply that here. Inserting my own made up radius of 2 for the sun and 20 for Capella, I come up with the answer being "100 times as luminous". But I fee like I am missing something...

no, that's fine …

that's exactly how these "dimensional analysis" questions work …

R²/L is a constant

so if you multiply R by 10, you do multiply L by 100 ​