Question

IN MYOPIA OBJECT Distance Is infinity and image distance is equal to Far point=D.Find focal length and which lens is used?

Answer 1

u=-infinity

v=-D(because of the concave lens it is minus)

1/f=1/v-1/u(lens formula)

1/f=1/-D-1/-infinity

1/f=1/-D+0

1/f=1/-D

f =-D

Bi concave lens is used