One face AC of the glass prism is silvered as shown and the principal section of a glass prism is an isosceles triangle ABC with AB=AC. The ABAC, if the ray incident normally on the face AB and after two reflections, it energies from the base BC. perpendicular to it, is:

Question

One face AC of the glass prism is silvered as shown and the principal section of a glass prism is an isosceles triangle ABC with AB=AC. The ABAC, if the ray incident normally on the face AB and after two reflections, it energies from the base BC. perpendicular to it, is: (A)  70°  (B)  36°  (C)  72°  (D)  44°

Tardigrade Admin · Accepted Answer

α +2β =180o and β =2α α =36o

Q. One face AC of the glass prism is silvered as shown and the principal section of a glass prism is an isosceles triangle ABC with AB=AC. The ABAC, if the ray incident normally on the face AB and after two reflections, it energies from the base BC. perpendicular to it, is:

$70^{\circ}$

$36^{\circ}$

$72^{\circ}$

$44^{\circ}$

$α + 2 β = 180^{o}$ and $β = 2 α$ $α = 36^{o}$