Question

According to Rayleigh's criterion for the angular separation between two resolvable objects, the correct relation is:

Options

• \[\sin\theta = \frac{\lambda}{1.22\, d}\]

• \[\sin\theta = 1.22\,\frac{\lambda}{d}\]

• \[\sin\theta = \frac{1.22\, d}{\lambda}\]

• \[\sin\theta = \frac{\lambda d}{1.22}\]

Answer 1

The angular separation between two resolvable objects is given by Rayleigh's criterion: \[\sin\theta = 1.22\,\frac{\lambda}{d}\], where d is the aperture of the telescope. Since resolving power is the inverse of angular separation, a larger aperture d gives a smaller \[\theta\] and hence better resolving power.