The penetration of light into the region of geometrical shadow is called:

If $\lambda = 6000 \, \mathring{A}$ and $a = 18 \times 10^{-5} \, \text{cm}$,find the angular width of the central maximum in degrees $(^\circ)$.

Light of wavelength $\lambda$ is incident on a single slit of width $a$ and the distance between the slit and the screen is $D$. In the diffraction pattern, if the slit width is equal to the width of the central maximum, then $D$ is equal to:

The angular spread of the central maximum in a diffraction pattern does not depend on . . . . . . .

For the visibility of a diffraction pattern of a wave of light,the size of the slit or obstacle should be

Red light of wavelength $6500 \, \mathring{A}$ is incident on a slit of width $0.50 \, \text{mm}$. Find the distance between the two first minima on both sides of the central maximum in the diffraction pattern. The distance between the screen and the slit is $1.8 \, \text{m}$.