State the factors on which angle of minimum deviation of a prism depend.

Complete the following ray diagram. Surface $PR$ of prism $PQR$ in reflecting surface. Ray $AB$ in incident ray and ray $AC$ falls on the prism surface $PR$ normally. 

The figure shows refraction of light through a prism. Name angles  $A, B, C, D, E$ and $F$. Label incident, refracted and emergent rays.

The figure shows two light rays $OA$ and $OB$ from an object $O$. Show refracted ray in each case and obtain the image of $O$. Will this image be real or virtual?