Question

The central maximum in the diffraction pattern of a circular aperture is known as

• A. The Abbe disc
• B. The Airy disc
• C. The Poisson spot
• D. The Rayleigh spot

Answer 1

The correct option is B The Airy disc


In the diffraction pattern, due to a circular aperture consists of a bright circular disc as central maxima which is called Airy's disc.

The angular position of the first dark fringe at the outer edge of the Airy's disc is given as

$\beta =\frac{1.22\lambda }{b}$

Hence, option $\left(\text{B}\right)$ is correct.