A light ray traveling in a medium with n=1.5 strikes the boundary with n=1.0 at

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Question: A light ray traveling in a medium with n=1.5 strikes the boundary with n=1.0 at 50°. What occurs?

Options:

Correct Answer: Total internal reflection

Solution:

Since 50° is greater than the critical angle (θc ≈ 41.8°), total internal reflection occurs.

A light ray traveling in a medium with n=1.5 strikes the boundary with n=1.0 at 50°. What occurs?

A light ray traveling in a medium with n=1.5 strikes the boundary with n=1.0 at 50°. What occurs?

Step 1: Identify the two media involved. The first medium has a refractive index (n) of 1.5, and the second medium has a refractive index of 1.0.
Step 2: Determine the angle of incidence. The light ray strikes the boundary at an angle of 50°.
Step 3: Calculate the critical angle (θc) using the formula: θc = arcsin(n2/n1), where n1 is the refractive index of the first medium (1.5) and n2 is the refractive index of the second medium (1.0).
Step 4: Calculate θc: θc = arcsin(1.0/1.5) ≈ 41.8°.
Step 5: Compare the angle of incidence (50°) with the critical angle (41.8°). Since 50° is greater than 41.8°, total internal reflection occurs.
Step 6: Conclude that when the angle of incidence is greater than the critical angle, the light ray does not pass into the second medium but reflects back into the first medium.

Refraction and Total Internal Reflection – Understanding how light behaves at the boundary between two media with different refractive indices, including the concept of critical angle.