- Draw a labelled ray diagram showing the formation of image by a compound microscope in normal adjustment. Derive the expression for its magnifying power.
- How does the resolving power of a microscope change when.
- The diameter of the objective lens is decreased,
- The wavelength of the incident light is increased.
CBSE OUTSIDE DELHI - SET 2 AJMER 2015
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Derivation:
- Magnification due to objective $\text{M}_{\circ} = \frac{\text{L}}{\text{f}_{\circ}}$
- Magnification due to eyelens $\text{M}_{e} = \frac{\text{D}}{\text{f}_{e}}$
- Total magnification m $ = \text{m}_{\circ}\text{m}_{e}$
$\text{m}_{\circ} = \frac{\text{L}}{\text{f}_{\circ}}.\frac{\text{D}}{\text{f}_{e}}$
- The resolving power of microscope.
- Will decrease with decrease of the diameter of objective lens as resolving power is directly proportional to the diameter.
- Will decrease with increase of the wavelength of the incident light as resolving power is inversely proportional to the wave length.
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