Monochromatic light of wavelength $580 \,nm$ is incident on a slit of width $0.30 \,mm$. The screen is $2 \,m$ from the slit. The width of the central maximum is ........... $\times 10^{-3} \,m$.

The condition for observing Fraunhofer diffraction from a single slit is that the light wavefront incident on the slit should be

The angular spread of the central maximum in a diffraction pattern does not depend on . . . . . . .

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

$A$ light wave of wavelength $\lambda$ is incident on a slit of width $d$. The resulting diffraction pattern is observed on a screen at a distance $D$. If the linear width of the principal maxima is equal to the width of the slit,then the distance $D$ is:

Assertion : When a tiny circular obstacle is placed in the path of light from some distance,a bright spot is seen at the centre of the shadow of the obstacle.
Reason : Destructive interference occurs at the centre of the shadow.