A fiber optic cable uses total internal reflection. If the refractive index of t
Practice Questions
Q1
A fiber optic cable uses total internal reflection. If the refractive index of the core is 1.5 and that of the cladding is 1.4, what is the critical angle?
42.0°
48.6°
60.0°
30.0°
Questions & Step-by-Step Solutions
A fiber optic cable uses total internal reflection. If the refractive index of the core is 1.5 and that of the cladding is 1.4, what is the critical angle?
Step 1: Identify the refractive indices. The refractive index of the core (n1) is 1.5 and the refractive index of the cladding (n2) is 1.4.
Step 2: Use the formula for the critical angle, which is θc = sin⁻¹(n2/n1).
Step 3: Substitute the values into the formula: θc = sin⁻¹(1.4/1.5).
Step 4: Calculate the value of 1.4 divided by 1.5, which is approximately 0.9333.
Step 5: Find the inverse sine (sin⁻¹) of 0.9333 using a calculator or trigonometric table.
Step 6: The result is approximately 42.0 degrees, which is the critical angle.
Total Internal Reflection – The phenomenon where light is completely reflected within a medium when it hits the boundary at an angle greater than the critical angle.
Refractive Index – A measure of how much the speed of light is reduced inside a medium compared to vacuum.
Critical Angle – The minimum angle of incidence at which total internal reflection occurs, dependent on the refractive indices of the two media.
