The radius $r$ of the $n^{th}$ half-period zone is proportional to:

How will the diffraction pattern change when yellow light is replaced by blue light? The fringes will be

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

Which of the following colourful patterns is due to the diffraction of light?

If the width of the slit is $a$,then the value of the first secondary maximum in a single slit diffraction pattern is given by:

In Fraunhofer diffraction by a single slit,the width of the slit is $0.01 \ cm$. If the wavelength of the light incident normally on the slit is $5000 \ \mathring{A}$,the angular distance of the second maxima from the midline of the central maxima is . . . . . . $\text{rad}$.