Question

A concave lens forms the image of an object such that distance between object and image is 10 cm and the magnification produced is $\frac { 1 } { 4 }$. The focal length of the lens will be

• A. 8.6 cm
• B. 6.2 cm
• C. 10 cm
• D. 4.4 cm

Answer 1

Answer: (D)

4.4 cm

Answer 2

Concave lens forms virtual image of a real object. So

u = – 4x ; v = – x

Distance between object and image is

\ f = – 4.4 cm