Question

A person is nearsighted with a far point of 75.0 cm. a. What focal length contact lens is needed to give him normal vision

Answer 1

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

`f= -75 \ cm = - 0.75 \ m`

b

`P = -1.33 \ diopters`

Step-by-step explanation:

From the question we are told that

The image distance is
`d_i = -75 cm`

The value of the image is negative because it is on the same side with the corrective glasses

The object distance is
`d_o = \infty`

The reason object distance is because the object father than it being picture by the eye

General focal length is mathematically represented as

`(1)/(f) = (1)/(d_i) - (1)/(d_o)`

substituting values

`(1)/(f) = (1)/(-75) - (1)/(\infty)`

=>
`f= -75 \ cm = - 0.75 \ m`

Generally the power of the corrective lens is mathematically represented as

`P = (1)/(f)`

substituting values

`P = (1)/(-0.75)`

`P = -1.33 \ diopters`