A silica optical fibre has a core refractive index and a cladding refractive index

PHYSICS · Single correct · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments

Problem

A silica optical fibre has a core refractive index

n_{\text{core}} = 1.48

and a cladding refractive index

n_{\text{clad}} = 1.44

. The critical angle for light at the core–cladding boundary (measured inside the core) is closest to (a)

70^{\circ}

(b)

77^{\circ}

(c)

60^{\circ}

(d)

90^{\circ}