Question

(a) Draw a ray diagram showing the image formation by a compound microscope. Obtain expression for total magnification when the image is formed at infinity. 

(b) How does the resolving power of a compound microscope get affected, when 

(i) focal length of the objective is decreased. 

(ii) the wavelength of light is increased ? Give reasons to justify your answer.

Answer 1

(a) The ray diagram, showing image formation by a compound microscope, is given below :

Here, L = tube length = distance between the second focal point of the objective and the first focal point of the eyepiece.

When the final image is formed at infinity, the angular magnification due to the eyepiece equals