Snell's Law and the Refraction of Light

In summary, the conversation discusses a problem involving a rectangular block of glass surrounded by liquid carbon disulfide and a ray of light incident on the glass at a certain angle. The formula n1sin theta1 = n2 sin theta2 is used to find the angle of refraction at point B, but it is incorrect. The correct approach is to apply Snell's law twice and take into account the non-parallel surfaces. After understanding the need for geometry in the problem, the correct angle of refraction can be determined.
  • #1
BoogieL80
39
0
I've gotten stuck on the following problem:

The drawing shows a rectangular block of glass (n = 1.52) surrounded by liquid carbon disulfide (n = 1.63). A ray of light is incident on the glass at point A with a = 34.0° angle of incidence. At what angle of refraction does the ray leave the glass at point B?


http://www.boomspeed.com/boogiel80/refraction.gif [Broken]

I was using the formula n1sin theta1 = n2 sin theta2 and manipulated the foruma for sin theta2 (I assumed the liquied was n1 and the glass was n2). I then found the inverse sin of my answer to get the angle. I got an answer of 36.8 degrees. Webassign told me that was incorrect. I thought that maybe since the angle was going back into the same liquid that maybe it would be the same as the angle of incidence, but that was also incorrect. Any feedbook would be appreciated.
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
Snell's law is the appropriate way to attack the problem, but you need to apply it twice. Once for going into the glass and once for leaving it. Be careful to note that these surfaces are not parallel so you will have to do some geometry to relate angles.
 
  • #3
Physics Monkey said:
Snell's law is the appropriate way to attack the problem, but you need to apply it twice. Once for going into the glass and once for leaving it. Be careful to note that these surfaces are not parallel so you will have to do some geometry to relate angles.
My only thing with that method is that I get the beginning angle (33.9 in my calculations). That makes sense to me, because I learned from reading that if you have a transparent material emmersed in a material, n1 should equal n3 and thus theta1 should equal theta3, but webbassign is saying that answer is incorrect. Should the angle really be something else other than the original angle?
 
  • #4
Physics Monkey said:
Snell's law is the appropriate way to attack the problem, but you need to apply it twice. Once for going into the glass and once for leaving it. Be careful to note that these surfaces are not parallel so you will have to do some geometry to relate angles.
Actually I figurd out what you meant by "doing some geometry". Thanks again.
 

What is Snell's Law?

Snell's Law, also known as the law of refraction, is a formula that describes how light bends when it passes through different mediums. It states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities of light in the two mediums.

How does Snell's Law explain the refraction of light?

Snell's Law explains the refraction of light by showing how the change in density or composition of a medium affects the speed of light and therefore causes it to bend as it passes through. This phenomenon can be observed when light passes through a prism or a glass of water, causing the light to change direction.

What factors affect the refraction of light?

The refraction of light is affected by the difference in density between two mediums, the angle at which the light enters the medium, and the wavelength of the light. The denser the medium, the slower the speed of light and the more it will bend. The angle of incidence also plays a role, as a larger angle will result in a larger change in direction.

What is the relationship between Snell's Law and the critical angle?

The critical angle is the angle of incidence at which the refracted ray will travel along the surface of the medium instead of passing through it. This angle is related to Snell's Law because when the angle of incidence reaches the critical angle, the sine of the angle of refraction becomes 1, which means that the refracted ray will be parallel to the surface of the medium.

How is Snell's Law used in real life?

Snell's Law is used in many real-life applications, such as in the design of lenses for glasses and cameras, the construction of prisms for optical instruments, and the production of fiber optic cables. It is also used in the study of atmospheric refraction, which affects the visibility of objects in our atmosphere, and in the development of corrective eye surgeries.

Similar threads

  • Introductory Physics Homework Help
Replies
1
Views
863
  • Introductory Physics Homework Help
Replies
8
Views
4K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
5K
  • Introductory Physics Homework Help
Replies
7
Views
6K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
949
  • Introductory Physics Homework Help
Replies
4
Views
2K
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
4K
Back
Top