Linear magnification produced by a mirror is +1.5

The correct answer is Option (2) → It is a concave mirror with object between F and Pole

The linear magnification of a mirror is \( m = -\frac{v}{u} \). A positive value means an erect (virtual) image, and a magnitude greater than 1 means it is enlarged. A convex mirror always gives a diminished image, so a magnified image needs a concave mirror.

For a concave mirror the mirror formula gives \( m = \frac{f}{f - u} \) with the sign convention \( f \lt 0 \), \( u \lt 0 \). Writing magnitudes, \( f = -|f| \) and \( u = -|u| \):

    \( \displaystyle m = \frac{|f|}{|f| - |u|} \)

This is positive and greater than 1 only when \( |u| \lt |f| \), that is, when the object is between the pole and the focus. For \( m = +1.5 \), \( |u| = |f|/3 \).

Why the other options are incorrect

• Option (1) It is a concave mirror with object between F and 2F — Incorrect. The image is real and inverted, so m is negative.

• Option (3) It is a convex mirror with object at infinity — Incorrect. A convex mirror gives a highly diminished image at its focus, so m is close to 0.

• Option (4) It is a convex mirror with object anywhere in front of the mirror. — Incorrect. A convex mirror always gives an erect image with m between 0 and 1, never 1.5.