Advertisement Remove all ads

A Simple Microscope Has a Magnifying Power of 3.0 When the Image is Formed at the Near Point (25 Cm) of a Normal Eye. - Physics

Answer in Brief

A simple microscope has a magnifying power of 3.0 when the image is formed at the near point (25 cm) of a normal eye. (a) What is its focal length? (b) What will be its magnifying power if the image is formed at infinity?

Advertisement Remove all ads


For the simple microscope, we have:
Least distance of clear vision, D = 25 cm
Magnifying power, m = 3
Let the focal length be f.

(a) When the image is formed at D = 25 cm, the magnifying power of the simple microscope is given by

m = 1 + `(D/f)`

`=> 3 =1+(25/f)`

`=> 25/f = 2`

`=> f = 25/2 = 12.5  "cm"`

(b) When the image is formed at infinity in normal adjustment, the magnifying power is given by

`m = D/f = 25/12.5 =2.0`

So, the magnifying power is 2 if the image is formed at infinity.

Concept: Magnification
  Is there an error in this question or solution?
Advertisement Remove all ads


HC Verma Class 11, 12 Concepts of Physics 1
Chapter 19 Optical Instruments
Q 3 | Page 432
Advertisement Remove all ads

Video TutorialsVIEW ALL [1]

Advertisement Remove all ads

View all notifications

      Forgot password?
View in app×