A point object O is situated on the principal axis of a convex lens having a focal length f = 20 cm , at a distance of 40 cm to its left. The lens has a diameter of 10 cm . An eye is positioned 60 cm to the right of the lens and at a distance h below the principal axis. The maximum value of h for which the image is visible is

Step-by-step solution

Using the lens formula to find the position of the image: 1 v - 1 u = 1 f Substituting u = -40 cm and f = 20 cm : 1 v - 1 -40 = 1 20 1 v = 1 20 - 1 40 = 1 40 v = 40 cm The image is formed at a distance of 40 cm to the right of the lens. The rays from the object pass through the lens aperture, which has a radius of R = 10 2 = 5 cm , and converge at the image point. After converging at the image, the rays diverge. The eye is positioned 60 cm to the right of the lens, which is at a distance of 60 - 40 = 20 cm from the