Q12: A light ray is travelling from a medium with a larger index of refraction to a medium with a smaller index of refraction. Describe what happens as the angle of incidence gets larger and larger. Include the concept of the critical angle in your discussion.
The ray of refraction would bend away from the normal. That's all I've got, sorry!
When a light ray travels from a medium with a larger index of refraction to a medium with a smaller index of refraction, its behavior depends on the angle of incidence. The angle of incidence is the angle between the incident ray and the normal (a line perpendicular to the surface of separation between the two media) at the point of incidence.
As the angle of incidence gets larger and larger, several things can happen:
1. Refraction: Generally, when light travels from one medium to another with a different refractive index, it changes direction. This phenomenon is called refraction. The amount of bending (refraction) depends on the angle of incidence and the refractive indices of the two media involved.
2. Bending away from the normal: As the angle of incidence gets larger, the light ray bends away from the normal. This bending is due to the change in speed of the light when it enters a medium with a different refractive index.
3. Critical angle: As the angle of incidence continues to increase, there is a specific angle known as the critical angle. The critical angle is the angle of incidence that results in an angle of refraction of 90 degrees (i.e., the light ray travels parallel to the boundary between the two media). At the critical angle, the light ray is refracted at an angle of 90 degrees with respect to the normal.
4. Total internal reflection: If the angle of incidence is larger than the critical angle, a phenomenon called total internal reflection occurs. In this case, no light is refracted into the second medium, and all the light is reflected back into the original medium. Total internal reflection is possible when the light ray travels from a medium with a higher refractive index to a medium with a lower refractive index.
To determine the critical angle and whether total internal reflection will occur, you need to know the refractive indices of the two media involved. The critical angle can be calculated using the formula:
sin(critical angle) = refractive index of the second medium / refractive index of the first medium.
By substituting the refractive indices into this formula, you can find the critical angle and determine if total internal reflection will occur or not.