Reflection and Refraction formula help

[Muhammad Danish]

Homework Statement

2. Homework Equations

3. The Attempt at a Solution [/B]
I tried to solve this question with the general formula n=sin i / sin r. 1.5 = sin 30/sin r,
r = 19.4 = 19 which is option A. But option A is incorrect. Please guide me where am I wrong..

 

[Orodruin]

The incident angle is not 30 degrees.

 

[Muhammad Danish]

The incident angle is not 30 degrees.

60 degrees??

 

[Orodruin]

50 degrees??

Why would it be 50 degrees?

 

[Muhammad Danish]

Why would it be 50 degrees?

Sorry I mean't 60 degrees, since 90-30 = 60

 

[Orodruin]

Sorry I mean't 60 degrees, since 90-30 = 60

Yes, the incident angle is the angle between the surface normal and the ray, not between the surface itself and the ray.

 

[Muhammad Danish]

Yes, the incident angle is the angle between the surface normal and the ray, not between the surface itself and the ray.

Thanks a lot for pointing that mistake out. I was making the same mistake in many questions like that.