A camera is equipped with a lens with a focal length of 21 cm. When an object 1.7 m (170 cm) away is being photographed, how far from the film should the lens be placed?

Answer 1

Assuming the lens is convex

U =- 170 cm F = 21 cm

Use

1/f = 1/V -1/U

1/21 = 1/V - 1/ 170

Gives V = 23.96 cm

Image is on the other side of the lens

Image is real inverted and diminished