Michelson Interferometer question

[zimo]

Homework Statement

Express the intensity from a beam that crosses a Michelson Interferometer that its beam splitter transfers 1/3 and reflects 2/3.

Homework Equations

N/A

The Attempt at a Solution

Would like to have a hint...

 

[ideasrule]

Light can take one of two paths in a Michelson interferometer. Call the initial intensity I0, and trace both paths to see what the final intensity is. Every time the light reflects, multiply the original intensity by 2/3; every time it transmits, multiply the intensity by 1/3.