Question

A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm .The focal length of this combination of lenses will be ?


​

Answer 1

Answer:

Answer:The focal length of this combination of lenses will be +20 cm. So, the focal length of this combination of lenses will be +20 cm. Hence, this is the required solution.

Answer 2

Answer:

hat would you like to ask?

12th

Physics

Ray Optics and Optical Instruments

Combination of Lenses

A convex lens of focal leng...

PHYSICS

Asked on January 17, 2020 byPulkit Shakil

A convex lens of focal length 10cm is placed in contact with a concave lens of focal length 20cm. The focal length of this combination of lenses will be :

A

+10cm

Your Answer

ANSWER

Given,

f1=+10cm for convex lens

f2=−20cm for concave lens

The focal length of the combination is given by

f1=f21+f21

f1=+10cm1+−20cm1=20cm1

f=+20cm