Light of wave length $5000A^{\circ}$ falls on a reflecting surface . What are the wave length and frequency of the reflected light ? For what angle of incidence is the reflected ray normal to the incident ray ?

Question

$\begin{array}{1 1} i=30^{\circ} \\ i=90^{\circ} \\ i=45^{\circ} \\ i=60^{\circ} \end{array}$