An object is placed between two plane mirrors inclined at some angle to each other. If the number of images formed is $7$, then the angle of inclination is: (in $^{\circ}$)

$A$ point source is placed at coordinates $(0,1)$ in the $xy$-plane. $A$ ray of light from the source is reflected on a plane mirror placed along the $X$-axis and perpendicular to the $xy$-plane. The reflected ray passes through the point $(3,3)$. What is the path length of the ray from $(0,1)$ to $(3,3)$?

$A$ man runs towards a plane mirror at a speed of $15 \, m/s$. The speed of the image relative to the man is $...... \, m/s$.

$A$ monochromatic beam of light enters a square enclosure with mirrored interior surfaces at an angle of incidence $\theta_i(\neq 0)$ (see figure). For some value$(s)$ of $\theta_i$,the beam is reflected by every mirrored wall (other than the one with the opening) exactly once and exits the enclosure through the same hole. Which of the following statements about this beam is correct?

If an observer is walking away from a plane mirror with a velocity of $6\;m/s$,then the velocity of the image with respect to the observer will be........$m/s$.

Find the angle of deviation for the given diagram.