Total internal reflection?

Question

An optical fiber uses flint glass clad with crown glass. What is the critical angle?

Answer 1

Total internal reflection is an optical phenomenon that occurs when a ray of light strikes a medium boundary at an angle larger than the critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary no light can pass through, so effectively all of the light is reflected. The critical angle is the angle of incidence above which the total internal reflection occurs.

The critical angle (minimum angle for total internal reflection) is determined by the difference in index of refraction between the core and cladding materials.

Answer 2

you must give the refraction index

else critical angle

calculate  n (crown glass)/n (flint glass)

take sin corresponding to that value