At what distance from a convex lens of focal length `30cm` an object should be placed so that the size of image be `(1)/(4) `that of object?

Options

A. 30 cm
B. 60 cm
C. 15 cm
D. 150 cm

Answer

D

Explanation

Image is real, because virtual image is enlarged.
`therefore " " (1)/(v)-(1)/(u)=(1)/(f)` or `(1)/(x//4)+(1)/(x)=(1)/(30) " " (because u=-x)`
`(5)/(x)=(1)/(30)`
`therefore " " x=150 cm`.