In a single slit diffraction of light of wavelength $\lambda$ by a slit of width $e$,the size of the central maximum on a screen at a distance $b$ is

$A$ beam of light of wavelength $600 \,nm$ from a distant source falls on a single slit $1 \,mm$ wide and the resulting diffraction pattern is observed on a screen $2 \,m$ away. The distance between the first dark fringe on either side of the central bright fringe is

If a narrow slit of width $2 \, mm$ is illuminated by monochromatic light of wavelength $500 \, nm$,then the distance between the first minima on both sides on a screen at a distance of $1 \, m$ is ....... $mm$.

For a parallel beam of monochromatic light of wavelength $\lambda$,diffraction is produced by a single slit whose width $a$ is of the order of the wavelength of the light. If $D$ is the distance of the screen from the slit,the width of the central maxima will be

The angular width of the central maxima in the Fraunhofer diffraction pattern of a slit is measured. The slit is illuminated by light of wavelength $6000 \ \mathring A$. When the slit is illuminated by light of another wavelength,the angular width decreases by $30\%$. The wavelength of this light will be ...... $\mathring A$.

When a compact disc $(CD)$ is illuminated by a small source of white light,coloured bands are observed. This is due to