Question

The near point of a person's eye is 70.4 cm. (Neglect the distance from the lens to the eye.) (a) To see objects clearly at a distance of 24.0 cm, what should be the focal length of the appropriate corrective lens? cm (b) To see objects clearly at a distance of 24.0 cm, what should be the power of the appropriate corrective lens? diopters

Answer 1

a) f = 17,898 cm , b) P = 5.58D

Step-by-step explanation:

a) For this exercise we must use the constructor equation

1 / f = 1 / p + 1 / q

where f is the focal length and p, q are the distance to the object and the image, respectively

in this case they tell us that the distance to the point of near vision is q = 70.4 cm, here the image must be so that the person can see it normally

1 / f = 1 / 24.0 + 1 / 70.4

1 / f = 0.05587

f = 17,898 cm

b) the power of a lens is defined as the inverse of the focal length in meters

P = 1 / d

p = 1 / 0.17898

P = 5.58D