Question

Calculate the numerical aperture of an optical fibre whose core and cladding are made of materials of refractive index 1.6 and 1.5 respectively.

(a) 0.55677

(b) 55.77

(c) 0.2458

(d) 0.647852

Answer 1

The correct answer is (a) 0.55677

To elaborate: Numerical aperture = (sqrt{n1^2-n2^2})

Numerical aperture = 0.55677.