$A$ person runs with a speed $u$ towards a bicycle moving away from him with speed $v$. The person approaches his image in the mirror fixed at the rear of the bicycle with a speed of:

Two plane mirrors are inclined at $70^{\circ}$. $A$ ray incident on one mirror at an angle $\theta$ with the surface,after reflection,falls on the second mirror and is reflected from there parallel to the first mirror. The value of $\theta$ is ......$^{\circ}$.

Two parallel mirrors $M_1$ and $M_2$ are separated by a distance $a$. An object is placed between them. What is the distance between the $n^{th}$ image formed by $M_1$ and the $n^{th}$ image formed by $M_2$?

$A$ mirror is placed at a distance of $60 \ m$ from the base of a tower. The angle between the top of the tower and the top of its image is $90^o$. Find the height of the tower in $m$.

$A$ ray of light makes an angle of $10^o$ with the horizontal above it and strikes a plane mirror which is inclined at an angle $\theta$ to the horizontal. The angle $\theta$ for which the reflected ray becomes vertical is......$^o$

The coordinates of the image with respect to the origin $c$ will be