Maximum diffraction takes place in a given slit for

When the frequency of the light used is changed from $4 \times 10^{14} \ s^{-1}$ to $5 \times 10^{14} \ s^{-1}$, the angular width of the principal (central) maximum in a single slit Fraunhofer diffraction pattern changes by $0.6 \ \text{radian}$. What is the width of the slit? (Assume that the experiment is performed in vacuum.)

Light of wavelength $550\, nm$ falls normally on a slit of width $22.0 \times 10^{-5}\, cm$. The angular position of the second minima from the central maximum will be (in radians)

Explain diffraction by a single slit.

In a diffraction experiment from a single slit,the angular width of the central maximum does $NOT$ depend upon:

Assertion: $A$ coloured spectrum is seen when we look through a muslin cloth.
Reason: It is due to the diffraction of white light on passing through fine slits.