When a plane mirror is rotated through an angle $\theta$,the reflected ray turns through an angle $2\theta$. What happens to the size of the image?

It is desired to photograph the image of an object placed at a distance of $3\;m$ from a plane mirror. The camera,which is at a distance of $4.5\;m$ from the mirror,should be focused for a distance of......$m$.

$A$ ray reflected successively from two plane mirrors inclined at a certain angle undergoes a deviation of $270^o$ after two reflections. The number of images observable is:

$A$ man $160\,cm$ high stands in front of a plane mirror. His eyes are at a height of $150\,cm$ from the floor. The minimum length of the plane mirror required for him to see his full-length image is......$cm$.

The reflecting surface of a plane mirror is vertical. $A$ particle is projected in a vertical plane which is also perpendicular to the mirror. The initial velocity of the particle is $10 \, m/s$ and the angle of projection is $60^\circ$ with the horizontal. The point of projection is at a distance $5 \, m$ from the mirror. The particle moves towards the mirror. Just before the particle touches the mirror,the velocity of approach of the particle and its image is ...... $m/s$.

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.