The photograph of a house occupies an area of 1.75 cm² on a 35 mm slide. The slide is projected on to a screen and the area of the house on the screen is 1.55 m². What is the linear magnification of the projector-screen arrangement.

The graph shows the variation of $v$ with a change in $u$ for a mirror. Points plotted above the point $P$ on the curve for values of $v$ are

A point object is moving along the principal axis of a concave mirror with uniform velocity towards the pole. Initially, the object is at infinite distance from pole on right side of the mirror as shown. Before the object collides with the mirror, how many times the distance between the object and its image is $40 \mathrm{cm}$?