The magnification of a real image formed by a concave mirror is always ...

For what position of the object does a convex lens form an erect and virtual image?

State the laws of refraction. Explain the phenomenon of refraction when a ray of light passes through a rectangular glass slab with the help of a ray diagram.

When light of two colours $A$ and $B$ is passed through a plane boundary; $A$ is bent more than $B$. Which colour travels more slowly in the second medium?

$A$ point object emits rays in all directions. Consider a ray emitted from the object that is parallel to the principal axis of the mirror. One of the points required to trace the reflected ray is the point of incidence itself,as shown in the figure. Select a point from the given figure through which the reflected ray passes.

If the radius of curvature of a concave mirror is $36\, cm$,what is its focal length (in $, cm$)?