If the refractive index of a medium is 2.0, what is the critical angle for total
Practice Questions
Q1
If the refractive index of a medium is 2.0, what is the critical angle for total internal reflection?
30°
45°
60°
90°
Questions & Step-by-Step Solutions
If the refractive index of a medium is 2.0, what is the critical angle for total internal reflection?
Correct Answer: 30°
Step 1: Understand that the refractive index (n) of a medium is given as 2.0.
Step 2: Recall the formula to find the critical angle (θc) for total internal reflection: θc = sin^(-1)(1/n).
Step 3: Substitute the value of n into the formula: θc = sin^(-1)(1/2.0).
Step 4: Calculate 1/2.0, which equals 0.5.
Step 5: Now, find the inverse sine (sin^(-1)) of 0.5. This gives you the critical angle.
Step 6: The inverse sine of 0.5 is 30 degrees.
Refractive Index – The refractive index is a measure of how much light slows down in a medium compared to vacuum.
Critical Angle – The critical angle is the angle of incidence above which total internal reflection occurs.
Total Internal Reflection – Total internal reflection is the phenomenon where light is completely reflected back into a medium when it hits the boundary at an angle greater than the critical angle.
