How to Calculate θ3 After Finding θ2 Using Snell's Law?

[betterscientist]

Homework Statement

Block A has a refractive index of 1.52, Block B has a refractive index of 1.2, and Block C has a refractive index of 1.4.
A ray of light travels through air into Block A. Assume air has a refractive index of 1 and θ1 = 78°.
Calculate angles θ2-θ8.

Relevant Equations

n1sin(θ1)=n1sin(θ2)

I used Snell's law to find θ2 as 40,1 (3sf) but now I'm stuck on finding θ3.

Is there a way to find θ3 without using geometry? How do I do this?

 

[BvU]

​

I'm stuck on finding θ3

How about using the same law again ?

Can you make (and post) a sketch of the situation ?

##\ ##

 

[betterscientist]

Apologies. I saw I have left out the image.

 

[BvU]

Good thing you now posted the picture. Differs from what I had in mind. And where is block C ? ?

 

[betterscientist]

Good thing you now posted the picture. Differs from what I had in mind. And where is block C ? ?

 

[betterscientist]

Sorry again. Cropped it out since it was irrelevant to the question I had issues with. I should have double checked my initial question/statement.

 

[BvU]

So far you found angle ##X_1##. So ##X_2 = ## ?
Now draw ##\theta_3## in the picture
Change of notation.
So far you found angle ##\theta_2##. So ##\theta_3 = ## ?

For ##\theta_4## you can use Snellius again. Etc..

##\ ##

 

[betterscientist]

So far you found angle ##X_1##. So ##X_2 = ## ?
Now draw ##\theta_3## in the picture
Change of notation.
So far you found angle ##\theta_2##. So ##\theta_3 = ## ?

For ##\theta_4## you can use Snellius again. Etc..

##\ ##

would theta 3 be the same as theta 2 (40,1)?

 

[haruspex]

would theta 3 be the same as theta 2 (40,1)?

Do they look the same?

 

[BvU]

Of course not.