In an optical fibre, core and cladding were made with materials of refractive indices 1.5 and 1.414 respectively . To observe total internal reflection , what will be the range of incident angle with the axis of optical fibre?

Question

\[\begin {array} {1 1} (1)\;0^{\circ}-60^{\circ} & \quad (2)\;0^{\circ}-48^{\circ} \\ (3)\;0^{\circ}-30^{\circ} & \quad (4)\;0^{\circ}-82^{\circ} \end {array}\]