By increasing the aperture of the objective lens, wavelength of light, focal length of the objective lens…

By increasing the aperture of the objective lens, wavelength of light, focal length of the objective lens and the resolving power of an astronomical telescope respectively
  1. is not affected, increases, decreases.
  2. increases, decreases, is not affected.
  3. decreases, increases, is not affected.
  4. is not affected, decreases, increases.

Solution

Resolving power of the telescope $\quad \mathrm{RP}=\frac{\mathrm{a}}{1.22 \lambda}$ where a is the diameter (aperture) of the objective lens. $\Longrightarrow \quad \mathrm{RP} \propto \mathrm{a}$ Thus the aperture of the objective lens is made so large so as to increase the resolving power of the telescope. .

Asked in: MHT CET 2020 (19 Oct Shift 2)

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