Question

calculate the focal length of a lens used in simple microscope so that magnifying power is +11. The least distance of distinct vision is 25 cm.

Plsss answer fast
Tommorow is my exam

Answer 1

Answer:

Explanation:

Given,

Focal length of convex lens, f=5cm

Position of image, v=25cm

Position of object, u=?

Apply lens formula

f

1 =

v

1

−

u

1

5

1

=

25

1

−

u

1

u=

4

25

cm

Magnifying power of instrument:

M=1+

f

D

M=1+

5

25

=6

Hence, object distance is

4

25

cm and magnifying power is 6

Answer 2

Explanation:

calculate the focal length of a lens used in simple microscope so that magnifying power is +11. The least distance of distinct vision is 25 cm.