A multi-mode optical fiber with a large core diameter has a core refractive index 𝑛1 = 1.5

Q. A multi-mode optical fiber with a large core diameter has a core refractive index 𝑛₁ = 1.5 and cladding refractive index 𝑛₂ = 1.4142. The maximum value of 𝜃_𝐴 (in degrees) for which the incident light from air will be guided in the optical fiber is ±                  .

Ans: 29-31