Unpolarised light is incident from the air on a plane surface of a material of refractive index $\mu$. At a particular angle of incidence $i$, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?

The interference pattern is obtained with two coherent light sources of intensity ratio $n$. In the interference pattern, the ratio $\frac{I_{max}-I_{min}}{I_{max}+I_{min}}$ will be

At the first minimum adjacent to the central maximum of a single slit diffraction pattern, the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is

A major breakthrough in the studies of cells came with the development of an electron microscope. This is because:

Two slits in Young's experiment have widths in the ratio of $1:25$. The ratio of intensity at the maxima and minima in the interference pattern $\frac{I_{max}}{I_{min}}$ is:

For a parallel beam of monochromatic light of wavelength $\lambda$, diffraction is produced by a single slit whose width $a$ is much greater than the wavelength of the light. If $D$ is the distance of the screen from the slit, the width of the central maxima will be:

In a diffraction pattern due to a single slit of width $a$, the first minimum is observed at an angle $30^\circ$ when light of wavelength $5000\text{ \AA}$ is incident on the slit. The first secondary maximum is observed at an angle of

In a double-slit experiment, when light of wavelength $400 \text{ nm}$ was used, the angular width of the first minima formed on a screen placed $1 \text{ m}$ away, was found to be $0.2^{\circ}$. What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? $\left(\mu_{\text{water}} = \frac{4}{3}\right)$

For Young's double-slit experiment, two statements are given below: Statement I: If screen is moved away from the plane of slits, angular separation of the fringes remains constant. Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases.