(a) Draw a labelled ray diagram to show the formation of an image by a compound microscope. Write the expression for its magnifying power. (b) How does the resolving power of a compound microscope change when (i) the refractive index of the medium between the object and the objective lens increases, and (ii) the wavelength of the radiation used is increased?
Solution
(a) The objective forms a real, inverted, magnified image of the object (placed just beyond ); the eyepiece further magnifies this as a virtual image at the near point. Magnifying power:
(b) Resolving power (numerical aperture ):
(i) resolving power \emph{increases}; (ii) resolving power \emph{decreases}.
(b) Resolving power (numerical aperture ):
(i) resolving power \emph{increases}; (ii) resolving power \emph{decreases}.
CBSE Class 12 Board · 2005 · All India · Subjective