Can the angle of refraction be equal to the angle of incidence?

In summary, Snell's law states that n1sin(theta1) = n2sin(theta2), where theta2 can be greater or less than theta1. If theta2 = theta1, there is no interface and the light continues in the same medium. However, it is possible to pretend there is an interface with equal indices of refraction on both sides, resulting in θ1 = θ2. In the case of two transparent substances with the same index of refraction, the angle of incidence and refraction are both 90 degrees.
  • #1
bobaustin
13
1
Snell's law says
n1sin(theta1) = n2sin(theta2)

The angle of refraction theta2 can be greater or less than the angle of incidence theta1. That's fairly obvious.

My question is if theta2 = theta1 then we don't have an interface (because n1 = n2) so the light is still in the same medium, and there is nothing to talk about?

Is there a case where there is an interface and theta2 = theta1 ?

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I think I found the answer: Pyrex rod in Wesson oil!
 
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  • #2
You can always pretend that there's an interface, with each side having the same n. Snell's law then tells you that θ1 = θ2, which makes sense since it just means that the light continues straight through as if there was no interface (which there isn't, of course).
 
  • #3
Doc Al said:
You can always pretend that there's an interface, with each side having the same n. Snell's law then tells you that θ1 = θ2, which makes sense since it just means that the light continues straight through as if there was no interface (which there isn't, of course).

How about the case that the OP pointed out: two transparent substances with the same index of refraction?

Of course, angle of incidence is also equal to the angle of refraction with the former is 90 degrees.
 

1. Can the angle of refraction be equal to the angle of incidence?

Yes, the angle of refraction can be equal to the angle of incidence in certain situations. This is known as the angle of refraction being equal to the angle of incidence or the angle of incidence being equal to the angle of refraction.

2. What is the angle of incidence?

The angle of incidence is the angle at which an incoming light ray strikes a surface or interface between two mediums.

3. What is the angle of refraction?

The angle of refraction is the angle at which a light ray is bent when it passes from one medium to another, such as from air to water.

4. What is Snell's Law?

Snell's Law is a fundamental law of physics that describes the relationship between the angle of incidence and the angle of refraction when a light ray passes from one medium to another. 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 speed of light in the first medium to the speed of light in the second medium.

5. Can the angle of refraction be greater than the angle of incidence?

Yes, the angle of refraction can be greater than the angle of incidence. This occurs when a light ray passes from a slower medium to a faster medium, causing the light to bend away from the normal line.

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