If $n$ represents the order of a half-period zone,the area of this zone is approximately proportional to $n^m$,where $m$ is equal to:

Assertion: The clouds in the sky generally appear to be whitish.
Reason: Diffraction due to clouds is efficient in equal measure at all wavelengths.

$A$ single slit diffraction pattern is formed with white light. For what wavelength of light, the $3^{\text{rd}}$ secondary maximum in the diffraction pattern coincides with the $2^{\text{nd}}$ secondary maximum in the pattern of red light of wavelength $6000 \text{ Å}$ (in $\text{ Å}$)?

$A$ slit of width $a$ is illuminated by red light of wavelength $6500 Å$. If the first diffraction minimum falls at $30^{\circ}$,then the value of $a$ is

The phenomenon that explains why light waves do not travel in a straight line is known as .......

Determine the angular separation between the central maximum and the first-order maxima of the diffraction pattern due to a single slit of width $0.25\, mm$ when light of wavelength $5890\,\mathring{A}$ is incident on it.