A beam of light in diamond (n=2.42) strikes the surface of water (n=1.33). What
Practice Questions
Q1
A beam of light in diamond (n=2.42) strikes the surface of water (n=1.33). What is the critical angle for total internal reflection?
25.5°
30.0°
36.9°
42.0°
Questions & Step-by-Step Solutions
A beam of light in diamond (n=2.42) strikes the surface of water (n=1.33). What is the critical angle for total internal reflection?
Step 1: Identify the refractive indices of the two materials. For diamond, n1 = 2.42 and for water, n2 = 1.33.
Step 2: Use the formula for critical angle, which is θc = sin⁻¹(n2/n1).
Step 3: Substitute the values into the formula: θc = sin⁻¹(1.33/2.42).
Step 4: Calculate the value of 1.33 divided by 2.42, which is approximately 0.549.
Step 5: Find the inverse sine (sin⁻¹) of 0.549 using a calculator, which gives approximately 36.9°.
Step 6: Conclude that the critical angle for total internal reflection is about 36.9°.
Snell's Law and Critical Angle – The critical angle is the angle of incidence above which total internal reflection occurs, calculated using the refractive indices of the two media.
