$A$ man of height $h$ requires a mirror to see his own complete image. The minimum height of the mirror required is:

The incident ray,reflected ray,and the outward drawn normal are denoted by the unit vectors $\overrightarrow{ a }, \overrightarrow{ b }$ and $\overrightarrow{ c }$ respectively. Choose the correct relation for these vectors.

Two mirrors are inclined at an angle $\theta$ as shown in the figure. $A$ light ray is incident parallel to one of the mirrors. The ray will start retracing its path after the third reflection if $\theta = ........$

The focal length of a plane mirror is .......

To obtain $3$ images using two plane mirrors, they should be placed at an angle of ....... $^o$.

Each of these diagrams is supposed to show two different rays being reflected from the same point on the same plane mirror. Which one of the following is correct?