Homework Help: Angle of deflection in a prism

1. Jul 19, 2011

Lindsayyyy

Hi,

Can anyone tell me how I get to the angle of deflection in a prism?

How do I get to

$$\delta=\alpha_{1}-\beta_{1}+\alpha_{2}-\beta_{2}$$

Thanks for the help

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2. Jul 19, 2011

xts

DO NOT POST YOUR HOMEWORK/COURSEWORK QUESTIONS HERE
and posting your question at the right place.

3. Jul 19, 2011

I like Serena

Hey Lindsayyyy!

Can you tell what the angles are in the top triangle, bounded by the dotted lines and the red line?

4. Jul 19, 2011

I like Serena

Ah yes, I missed that.

5. Jul 19, 2011

Lindsayyyy

Well, this is for understanind purpose. I thought homework section is actually for homework.
And actually I can't tell you :( I'm quite bad at trigonometry. I know that the sum in an angle is 180° but I don't know how I can express the unknown angles. I guess I find ,for example, alpha1 etc on another place in the drawing again, but I have no idea :/

6. Jul 19, 2011

I like Serena

Ah, but the homework section is also for coursework, and I think this qualifies.

Okay, let's take it a step back.
If we look at the angle α1.
What would be the angle opposite to this angle?
That is the angle on the inside of the prism, between the normal and the dotted line?

(Do you know what I mean with "the normal"?)

7. Jul 19, 2011

I like Serena

Let me mark it in the drawing.

Can you tell me what the angle marked with red is?

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8. Jul 19, 2011

Lindsayyyy

This is so distressing, I guess I should rather exmatricualte myself :/ I can't.

edit: just forget about it, this is senseless, would take hours for me to understand this, don't want to waste anyones time with this **** to be honest

9. Jul 19, 2011

I like Serena

Well, it's certainly not my intention to distress you.
But I don't feel like my time is wasted, so as long as you're up to it, so am I. :shy:

Actually, you should be able to see that the angle that I marked in red is about the same size as α1.
And it is the same size!

Are you? Up to it I mean?
If you don't want to continue that's fine too of course.

10. Jul 19, 2011

Lindsayyyy

as my english isn't that good, I'd rather say embarrasing instead of distressing. That I'am not even able to see such easy things. Goes on and on, as you already see in my other threads :/ I'm off to bed, thanks for your help though

11. Jul 19, 2011

I like Serena

All right.
If you change your mind and you do want to continue, just post in this thread.

Sleep well.

P.S.: and no, the only thing I saw in your other threads was an interest to learn stuff like electronics.