YDSE Vs Single Slit Diffraction

Q.

What are the two types of diffraction?

Q.

What is maxima and minima in diffraction?

Q. In a double slit experiment, green light of $5303\stackrel{\circ }{A}$ falls on a double slit having a separation of $19.44\mu m$ and a width of $4.05\mu m$. The number of bright fringes between the first and the second diffraction minima is :

1. $9$
2. $10$
3. $6$
4. $5$

Q. Light of wavelength $589.3\text{nm}$ is incident normally on the slit of width $0.1\text{mm}$. What will be the angular width of the central maximum, obtained on a screen placed at a distance of $1\text{m}$ from the slit?

1. ${0.67}^{\circ }$
2. ${1.02}^{\circ }$
3. ${1.34}^{\circ }$
4. None of the above

Q.

What is fringe width?

Q. In Young's double slit experiment, the separation between the slits is $0.1\text{mm}$, the wavelength of light used is $600\text{nm}$ and the interference pattern is observed on a screen $1\text{m}$ away from the slits. Find the separation between the successive bright fringes.

1. $2\text{mm}$
2. $6\text{mm}$
3. $4\text{mm}$
4. $3\text{mm}$

Q.

Two coherent sources of intensity ratio 100:1 interfere. The ratio of interference at the maxima and minima

1. 3:1 cm

2. 121:85 cm

3. 121:81 cm

4. 120:81 cm

Q. In Young's double slit experiment, a glass plate of refractive index $1.5$ and thickness $5\times {10}^{-4}\text{cm}$ is kept in the path of one of the rays, then

1. There will be no shift in the interference pattern.
2. Fringe width will increase.
3. Fringe width will decrease.
4. Optical path of the ray will increase by $2.5\times {10}^{-4}\text{cm}$

Q. The main difference in the phenomenon of interference and diffraction in light waves is that,

1. diffraction is due to interaction of light from the same wavefront whereas interference is the interaction of waves from two isolated sources.
2. diffraction is due to interaction of light from the same wavefront whereas interference is the interaction of two waves derived from the same source.
3. diffraction is due to interaction of waves derived from the same source, whereas interference is the bending of light from same wavefront.
4. diffraction is caused by reflected waves from a source where as interference is caused due to refraction of waves from a surface

Q.

What is the main principle used in interference?

Q. Visible light of wavelength $550\text{nm}$ falls on a single slit and produced its second diffraction minimum at an angle of ${45}^{\circ }$ relative to the incident direction of the light. What is the width of the slit $\left(\text{in}\mu \text{m}\right)$?

1. $2.4\mu \text{m}$
2. $1.4\mu \text{m}$
3. $1.56\mu \text{m}$
4. $2.56\mu \text{m}$

Q. What happens to the interference pattern if the two slits in a Young's experiment, are illuminated by two independent sources (such as two sodium lamps $S$ and $S^{\prime }$) as shown in figure?

1. Two sets of interference fringes overlap.
2. No fringes are observed.
3. The intensity of the bright fringes is doubled.
4. The intensity of the bright fringes becomes four times.

Q. In a Fraunhofer diffraction, at single slit of width $a$ with incident light of wavelength $5500\mathring{\text{A}}$, the first minimum is observed at an angle of ${30}^{\circ }$. The first secondary maximum will be observed at an angle $\theta$, equal to,

1. ${45}^{\circ }$
2. ${\sin }^{-1}\left(\frac{1}{4}\right)$
3. ${\sin }^{-1}\left(\frac{3}{4}\right)$
4. ${60}^{\circ }$

Q. A plane wave front of light of wavelength $6000\mathring{\text{A}}$ is incident upon a slit of $0.2\text{mm}$ width, which enables Fraunhofer's diffraction pattern to be obtained on a screen placed $2\text{m}$ away from the slit. Width of the central maxima $\left(\text{in mm}\right)$ will be,

1. $10$
2. $12$
3. $8$
4. $2$

Q.

Diffraction pattern cannot be observed with:

1. one wide slit

2. large number of narrow slits

3. two narrow slits

4. one narrow slit

Q. Light of wavelength $550\text{nm}$ passes through a narrow single slit of width $2.00\mu \text{m}$ and produces a diffraction pattern on the screen placed few meters away from the slit. Calculate the intensity relative to the central maximum at a point halfway between these two minima.

$\text{Take}:{\sin }^{-1}\left(0.275\right)={16}^{\circ }$
${\sin }^{-1}\left(0.550\right)={33.4}^{\circ },$
$\sin \left({24.7}^{\circ }\right)=0.417,$
$\sin \left(4.77\text{rad}\right)=-0.998$

1. $0.4$
2. $0.04$
3. $4$
4. $0.2$

Q. Match the column $\text{I}$ and column $\text{II}$ correctly.

Column $\text{I}$	Column $\text{II}$
$\left(A\right)$ Interference of light	$\left(p\right)$ $I=I_0{\cos }^2\theta$
$\left(B\right)$ Brewster's law	$(q$) Obstacle/aperature size $\approx \lambda$
$\left(C\right)$ Diffraction of light	$(r$) $\mu =\tan i_p$
$\left(D\right)$ Law of Malus	$\left(s\right)$ Coherent sources

1. $A-r,B-s,C-q,D-p$
2. $A-p,B-q,C-r,D-s$
3. $A-s,B-r,C-p,D-q$
4. $A-s,B-r,C-q,D-p$

Q.

For sustained interference fringes in double-slit experiment, essential condition is/are

1. Sources must be coherent
2. The intensities of the two sources must be equal

Here, the correct option(s)is/are

1. both $\left(1\right)$ and $\left(2\right)$

2. only $\left(1\right)$

3. only $\left(2\right)$

4. neither $\left(1\right)$ nor $\left(2\right)$

Q.

How many lenses are used in Fresnel diffraction?

Q. Two prism $\text{A}$ and $\text{B}$ in contact with each other. The dispersive power of $\text{A}$ and $\text{B}$ is $0.04$ and $0.03$ respectively. The angular dispersion produced by $\text{A}$ is $8^{\circ }.$ The angular dispersion produced by the combination, if the combination does not produce a net deviation is-

1. $8^{\circ }$
2. $6^{\circ }$
3. $4^{\circ }$
4. $2^{\circ }$

Q. What is difference between minima and maxima in diffraction ?

Q. Young's double-slit experiment is carried out with two thin sheets of thickness $10.4\mu \text{m}$ each and refractive index ${\mu }_1=1.52$ and ${\mu }_2=1.40$, covering the slits $S_1$ and $S_2$ respectively. If white light of range of wavelength $400\text{nm}$ to $780\text{nm}$ is used, which wavelength will form maxima exactly at point $O$, the center of the screen?

1. $12480\mathring{\text{A}}$ and $3120\mathring{\text{A}}$
2. $4160\mathring{\text{A}}$ and $3120\mathring{\text{A}}$
3. $6240\mathring{\text{A}}$ and $4160\mathring{\text{A}}$
4. $12480\mathring{\text{A}}$ and $4160\mathring{\text{A}}$

Q. (a) Define wavefront. Use Huygens' principle to verify the laws of refraction.
(b) How is linearly polarised light obtained by the process of scattering of light ? Find the Brewster angle for air-glass interface, when the refractive index of glass =1.5.

Q. Which of the following phenomena support the wave theory of light?

(a)	Scattering
(b)	Interference
(c)	Diffraction
(d)	Velocity of light in a denser medium is less than the velocity of light in the rarer medium.

1. A, B, C
2. A, B, D
3. A, C, D
4. B, C, D

Q. The main difference in the phenomenon of interference and diffraction in light waves is that,

1. diffraction is due to interaction of waves derived from the same source, whereas interference is the bending of light from same wavefront.
2. diffraction is caused by reflected waves from a source where as interference is caused due to refraction of waves from a surface
3. diffraction is due to interaction of light from the same wavefront whereas interference is the interaction of two waves derived from the same source.
4. diffraction is due to interaction of light from the same wavefront whereas interference is the interaction of waves from two isolated sources.

Q. Write four differences between interference and diffraction.

Q. Distinguish between the phenomenon of interference and diffraction of light.

Q. Distinguish between interference and diffraction.

Q. In Young's double slit experiment the two slits are illuminated by light of wavelength 5890${}^{\circ }$A and the distance between the fringes obtained on the screen is 0.2${}^{\circ }$. If the whole apparatus is immersed in water then the angular fringe width will be (refractive index of water is 4/3):

1. ${0.15}^{\circ }$
2. ${0.30}^{\circ }$
3. ${30}^{\circ }$
4. ${15}^{\circ }$

Q. In single slit diffraction pattern

1. Centre fringe has negligible width than others.
2. All fringes are of same width
3. Central fringe does not exist
4. None of the above