$A$ single slit diffraction pattern is formed with light of wavelength $6384 Å$. The second secondary maximum for this wavelength coincides with the third secondary maximum in the pattern for light of wavelength $\lambda_0$. The value of $\lambda_0$ is (in $Å$)

$A$ single slit of width $0.1\, mm$ is illuminated by a parallel beam of light of wavelength $6000\, \mathring{A}$ and diffraction bands are observed on a screen $0.5\, m$ from the slit. The distance of the third dark band from the central bright band is ........ $mm$.

The width of the $nth$ $HPZ$ (Half Period Zone) will be:

Angular width $(\beta)$ of the central maximum of a diffraction pattern on a single slit does not depend upon

Light of wavelength $580 \text{ nm}$ is incident normally on a slit of width '$a$'. The distance between the slit and the screen is $2.5 \text{ m}$ and the distance of the second order maximum from the centre of the screen is $14.5 \text{ mm}$ in a diffraction pattern. The value of '$a$' is

To observe diffraction,the size of the obstacle