The waves of $600 \ \mu m$ wavelength are incident normally on a slit of $1.2 \ mm$ width. The value of diffraction angle corresponding to the first minima will be (in radian) -

$A$ plane wave front of wavelength $\lambda$ is incident on a single slit of width $b$. What is the angular width of the secondary maximum?

$A$ 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 $Å$)

Red light of wavelength $5400 \ \mathring{A}$ from a distant source falls on a slit $0.80 \ mm$ wide. Calculate the distance between the first two dark bands on each side of the central bright band in the diffraction pattern observed on a screen placed $1.4 \ m$ from the slit. (in $mm$)

In a Fraunhofer diffraction at a single slit of width $d$ and incident light of wavelength $5500 \text{ Å}$,the first minimum is observed at an angle $30^{\circ}$. The first secondary maxima are observed at an angle $\theta=$

Due to which optical phenomenon do we not see the shadow of an opaque object clearly?