What is the power P of the eye when viewing an object 49 cm away? Assume the lens to retina distance is 2 cm.

Question

What is the power P of the eye when viewing an object 49 cm away? Assume the lens to retina distance is 2 cm.

Answer 1

Object distance

p = 49 cm

Position of the image from the lens:

q = 2 cm

Focal length is:

1/f = 1/q + 1/p

f = (1/2 + 1/49)^-1

f = 1.92 cm = 1.92 * 10^-2 m

The equation for Power is:

P = 1/f

P = 1/( 1.92 * 10^-2 m)

P = 52 Diopters