A biconvex lens has a radius of curvature of magnitude `20cm`. Which one of the following options describes best the image formed of an object of height `2cm` place `30 cm` from the lens ?

Options

A. Real, inverted, height = 1 cm
B. Virtual, upright, height = 1 cm
C. Virtual, upright, height = 0.5 cm
D. Real, inverted, height = 4 cm

Answer

D

Explanation

Lens maker’s formula
`(1)/(f) = (n - 1) ((1)/(R_(1)) - (1)/(R_(2)))`
`rArr (1)/(f) = (1.5 - 1) (2)/(R ) `
`rArr " " f = R = 20 ` cm
Magnification (m) = `(v)/(u) = (f)/(f+ u) = (I)/(O)`
`rArr (I)/(2) = (20)/(20 - 30) rArr I = -4 cm `
Image is real and inverted.