Question

A converging lens of focal length 5cm is placed at a distance of 20cm from a screen. How far from the lens should an object be placed so as to from its real image on the screen​

Answer 1

Answer:

f = 5 cm

u = - 20 cm

v = + v (Since image is real)

Lens formula : 1/v – 1/u = 1/f

1/v – 1/-20 = 1/5

1/v = 1/5 – 1/20 = (4 – 1)/20 = 3/20

V = 6.66