resolving power (conceptual)

Question

Resolving power of optical instrument improves when?

RankGuru · Accepted Answer

1. **Definition**: Resolving power is the ability of an instrument to show two closely spaced objects as separate entities.
2. **Rayleigh Criterion**: Two points are just resolved when the central maximum of one diffraction pattern falls on the first minimum of the other.
3. **Limit of Resolution ($\Delta \theta$)**: For a circular aperture of diameter $D$:
   - $\Delta \theta = \frac{1.22 \lambda}{D}$.
4. **Resolving Power (R.P.)**: Defined as the reciprocal of the limit of resolution: $R.P. = \frac{D}{1.22 \lambda}$.
5. **Optimization**: 
   - To **increase** R.P., we must **increase the aperture ($D$)** or **decrease the wavelength ($\lambda$)**.
6. **Conclusion**: Larger telescope mirrors (larger aperture) provide better resolution.

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resolving power (conceptual)

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