Question

the focal length of convex lens is 2.5 its power will be ____ d

Answer 1

Answer:

0.4

Explanation:

f = 2.5 m

P = 1/f = 1÷2.5 = 0.4 D

Answer 2

Answer:

11

Explanation:

f=2.5cm

v=−25cm

u

v

=?

u=?

f

1

=

v

1

−

u

1

2.5

1

=

25

−1

−

v

1

v

−1

=

25

10

+

2

v

−1

=

25

11

U=

11

−25

M=

u

−v

⇒=

u

−v

⇒

−25

−25×11

m=11