Question

if an image distance is minus 2 metre and the object distance is minus infinity then what is the power of the lens ?​

Answer 1

Answer:

The object at infinity and image at retina. As eye lens is a convex lens

so focal length is f=2.5cm=.025m

Now the power P=

f

1

=

.025

1

=40D

B) in this case object distance is u=−25 cm

and image is at retina v=2.5 cm

f

1

=

v

1

−

u

1

f

1

=

2.5

1

−

−25

1

f=25/11cm=

1100

25

m

Now the power P=

f

1

=

25/1100

1

=44D