The phenomenon of diffraction of light was discovered by

In deriving the single slit diffraction pattern,it is stated that the intensity is zero at angles of $\theta = n\lambda / a$,where $a$ is the slit width. Justify this by suitably dividing the slit to bring out the cancellation.

In a single slit diffraction experiment, the first minimum for red light $(660 \ nm)$ coincides with the first secondary maximum of some other wavelength $\lambda$. The value of $\lambda$ is $..... \mathring{A}$.

$A$ parallel monochromatic beam of light is incident normally on a narrow slit. $A$ diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first maximum of the diffraction pattern,the phase difference between the rays coming from the edges of the slit is

In the case of Fraunhofer diffraction due to a single slit,the intensity of the central maximum is $I_0$. If the width of the slit is doubled,what will be the new intensity of the central maximum?

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.)