$(i)$ Define a real image of an object.
$(ii)$ Name the mirror that:
$(a)$ can give a real as well as a virtual image of an object.
$(b)$ will always give a virtual image of the same size as the object.
$(c)$ will always give a virtual and diminished image of an object.
$(d)$ is used by a doctor in examining teeth.
$(iii)$ With the help of a ray diagram,explain the use of a concave mirror as a solar concentrator.

(N/A) $(i)$ $A$ real image is an image formed when the reflected light rays actually intersect at a point. It can be obtained on a screen.
$(ii)$ $(a)$ Concave mirror
$(b)$ Plane mirror
$(c)$ Convex mirror
$(d)$ Concave mirror
$(iii)$ $A$ concave mirror acts as a solar concentrator because it converges parallel rays of light coming from the sun at its principal focus. This concentration of light energy at the focus produces intense heat,which is used for solar heating applications. The ray diagram shows parallel rays from infinity incident on the concave mirror,which reflect and converge at the focus $F$.