A lens of focal length 12.0cm forms an upright image three times the size of a real object. The distance between the object and the images is

A lens of focal length 12.0cm forms an upright image three times the size of a real object. The distance between the object and the images is

Answer Details

F = 12cm, V = 3u

F = $\frac{uv}{u+v}$

12 = $\frac{u\times 3u}{u+3v}$

u = 16cm, and v = 48cm

therefore, distance between u and v

v = 48 - 16 = 32cm