Physics

Problem

A convex lens of focal length

20\,\text{cm}

forms a sharp image of an object on a screen placed

60\,\text{cm}

on the other side of the lens. How far from the lens is the object? a)

40\,\text{cm}

in front of the lens b)

30\,\text{cm}

in front of the lens c)

15\,\text{cm}

in front of the lens d)

60\,\text{cm}

in front of the lens