D. C. Pandey Solutions for Chapter: Interference and Diffraction of Light, Exercise 17: Objective Problems [Level 2]

Two ideal slits ${\mathrm{S}}_1$ and ${\mathrm{S}}_2$ are at a distance $d$ apart and illuminated by light of wavelength $\lambda$ passing through an ideal source slit $\mathrm{S}$ placed on the line through ${\mathrm{S}}_2$ as shown. The distance between the planes of slits and the source slit is $D$.

A screen is held at a distance $D$ from the plane of the slits. The minimum value of $d$ for which there is darkness at $\mathrm{O}$ is

Light of wavelength $589.3 \mathrm{nm}$ is incident normally on two slits of separation $0.1 \mathrm{mm}$ width $0.01 \mathrm{nm}$. The angular width of the central diffraction maximum at a distance of $1 \mathrm{m}$ from the slits is

A beam of light parallel to central line $\mathrm{AB}$ is incident on the plane of slits. The number of minima obtained on the large screen is $n_1$. Now, if the beam is tilted by some angle $\left(\ne 90°\right)$ as shown in the figure, then the number of minima obtained is $n_2$. Then

The intensity of each of the two slits in Young's double slit experiment is $I_0$. Calculate the minimum separation between the two points on the screen, where intensities are $2I_0$ and $I_0$. Given, the fringe width equal to $\alpha$.

The Young's double slit experiment is made in a liquid. The tenth bright fringe in liquid lies in screen whereas sixth dark fringe lies in vacuum. The refractive index of the liquid is approximately,

A parallel beam of light of intensity $I$ is incident on a glass plate. $25\%$ of light is reflected in any reflection by upper surface and $50\%$ of light is reflected by any reflection from lower surface. Rest is refracted. The ratio of maximum to minimum intensity in the interference region of reflected rays is

Assertion: In Young's double-slit experiment, often both the phenomena interference and diffraction are present.

Reason: Diffraction results due to the superposition of wavelets from different points of some wavefront.

Assertion: In the diffraction phenomenon, different maxima have different intensities.

Reason: In interference, different maxima have the same intensities.