A convex lens of focal length 30 cm forms an image of height 2 cm of an object placed at infinity. Now a concave lens of focal length 20 cm is placed at a distance of 26 cm to the side in which image is formed. The height of image formed by the combined system of the same object is

2.5 cm

For concave lens,

f = -20 cm

u = +4 cm

$m=\frac{F}{u+F}=\frac{-20}{+4-20}=\frac{-20}{-16}=\frac{5}{4} $

$\frac{I}{O}=\frac{v}{4}=\frac{5}{4}$

I = +2.5 cm

∴ (a)