To observe the diffraction phenomenon, the minimum size of the hole is needed for which of the following waves.

In a single slit diffraction pattern, which of the following is incorrect for fringe pattern?

When separation between the central maxima of the two objects is less than the separation between central maximum of first object and the first minima of the second object, then the objects are said to be

In the set up shown in figure, the two slits $S_1$and $S_2$ are not equidistant from the slit S, then central fringe at ' $\mathrm{O}$ ' is

If $a$ is the slit width and $\lambda$ is the wavelength of light used. Then, condition for diffraction is:

What will be the angle of diffraction for the first minimum due to Fraunhofer diffraction with sources of light of wavelength $550 \mathrm{nm}$ and slit of width $0.55 \mathrm{mm}$?

In the far field diffraction pattern of a single slit under polychromatic illumination, the first minimum with the wavelength $\lambda_{1}$ is found to be coincident with the third maximum at $\lambda_{2} .$ So

Light of wavelength $\lambda =5000$ $\mathrm{\AA }$ falls normally on a narrow slit. A screen is placed at a distance of $1 \mathrm{m}$ from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at $5 \mathrm{mm}$ from the centre of central maximum. The width of the slit is