Question

Object distance60 lmage distance 20 what is the focal length of lens ?

Answer 1

Answer:

As we know,

1/F=1/V-1/U

=1/20-1/60

=3-1/60

=2/60

1/F=30

Answer 2

Answer:

15

Explanation:

1/f = 1/x + 1/y

1/f = 1/60 + 1/20

1/f = 4 /60 = 1/15

f = 15