$A$ plane wavefront $(\lambda = 6 \times 10^{-7} \, m)$ falls on a slit $0.4 \, mm$ wide. $A$ convex lens of focal length $0.8 \, m$ placed behind the slit focuses the light on a screen. What is the linear diameter of the second maximum in $mm$?

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 . . . . . . $\text{rad}$.

$A$ slit of width $12 \times 10^{-5} \ cm$ is illuminated by monochromatic light of wavelength $6000 \ \mathring A$. Find the half angular width of the central bright maximum in the Fraunhofer diffraction pattern in degrees $(^o)$.

$A$ diffraction pattern is obtained by using a beam of red light. What will happen if the red light is replaced by blue light?

$A$ Fraunhofer diffraction pattern due to a single slit of width $0.3 \text{ mm}$ is obtained on a screen placed at a distance of $3 \text{ m}$ from the slit. The first minima lie at $5.5 \text{ mm}$ on either side of the central maximum on the screen. The wavelength of light used is (in $\text{ Å}$)

In a diffraction pattern due to a single slit,the angular width of the central maxima becomes half when the wavelength of the light used is changed from $\lambda$ to $7000 Å$. Then the value of $\lambda$ is (in $Å$)