Question

A given individual is unable to see objects clearly when he is beyond 60 cm. What power lens should be used to correct this problem? A) -12.932039 D (B) -0.74D (C) -0.828 D (D) -3.529412 D (E) -1.667 Diopters

Answer 1

correct option is E

power lens is - 1.667 D

Step-by-step explanation:

Given data

infinity = 60 cm

to find out

power lens

solution

we know here infinity v = -60 cm because object at infinity

and we take u = - infinity

so we know that

1/f = 1/v - 1/u

1/f = 1 / -60 - 1 / -infinity

so

1/f = - 1/60

f = - 60 cm = 0.60 m

and we know power of lens = 1/f

so here

power = 1 / -0.60

power = - 1.667 D

so correct option is E

power lens is - 1.667 D