What is the critical angle for a glass-air interface if the refractive index of
Practice Questions
Q1
What is the critical angle for a glass-air interface if the refractive index of glass is 1.5?
30 degrees
45 degrees
60 degrees
90 degrees
Questions & Step-by-Step Solutions
What is the critical angle for a glass-air interface if the refractive index of glass is 1.5?
Step 1: Understand that the critical angle is the angle of incidence above which total internal reflection occurs.
Step 2: Know that the formula to find the critical angle (θc) is θc = sin^(-1)(1/n), where n is the refractive index of the second medium (air in this case).
Step 3: Identify the refractive index of glass, which is given as 1.5.
Step 4: Since we are looking for the critical angle at a glass-air interface, we need to use the refractive index of air, which is approximately 1.0.
Step 5: Substitute the values into the formula: θc = sin^(-1)(1/1.5).
Step 6: Calculate 1/1.5, which equals approximately 0.6667.
Step 7: Use a calculator to find sin^(-1)(0.6667). This gives you approximately 41.81 degrees.
Step 8: Round the answer if necessary, but the critical angle is approximately 41.81 degrees.
