Physics

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}

77^{\circ}

60^{\circ}

90^{\circ}