Two mirrors meet at a 135 degree angle.... (light ray question)

[kspex2]

Homework Statement

Two mirrors meet at a 135 degree angle. If light rays strike one mirror at 40 degrees as shown, at what angle do they leave the second mirror?

Relevant Equations

none for this one, it's a visual problem

I tried to use complementary angles and the law of reflection but I still have no idea how to find the angle.

 

[berkeman]

Please show your work. We cannot help until you post your detailed effort to work on the solution. Thank you.

 

[kspex2]

I tried to think it through, didn't really have any work; I think I'm just missing something really simple.

 

[berkeman]

I tried to think it through, didn't really have any work; I think I'm just missing something really simple.

Draw-it-on-paper...

 

[kspex2]

Can't find what angle C is. I already have the answer I just don't know how to get there, how can we know what angle C is?

 

[kspex2]

 

[haruspex]

View attachment 269997

The 40 degree angle is from the horizontal line to a line sloping down from the left.
The angle you have labelled C is from that sloping line to the continuation of the horizontal line, yes?
What is the total of those two angles, i.e. from a line going one way from a point to a line going in exactly the opposite direction from the same point?

What angle does the “95°" you have marked refer to?
It will aid discussion if you label some points in your diagrams.

 

[berkeman]

Keep going! You need to find the angle that the ray leaves the 2nd mirror. With some good labeling of the ray angles and the mirror angles, you will have it!

 

[kspex2]

Ohhhhhh I see a triangle now... meaning it's 180-135-30 = 5 so 5 degrees.

 

[berkeman]

Ohhhhhh I see a triangle now... meaning it's 180-135-30 = 5 so 5 degrees.

I'm with @haruspex on this -- can you please add more labels to your diagram that shows angles with respect to what? That should help you also in finalizing your answer to the problem. Thanks.

 

[haruspex]

Ohhhhhh I see a triangle now... meaning it's 180-135-30 = 5 so 5 degrees.

You mean 180-135-40 = 5, right?