Question

If focal length lens suggest for a person suffering from hypermetropia is 100cm.find the near point "d" and power of lens

Answer 1

Answer:

power of lense:1/f(m)

Explanation:

person suffering from hypermetropia uses a biconvex lens.

Given: focal length of lens, f = 100 cm

Power = 100/f = 100/100 = 1 dioptre

Let the distance of near point be d

using formula: f = 25d/(d-25)

100 = 25d/(d-25)

100(d-25) = 25d

100d – 2500 = 25d

100d-25d = 2500

75d = 2500

d = 2500/75 = 33.33 cm

d = 33.33 cm