Fringe Width in YDSE

Q.

What is angular fringe width?

Q.

If a transparent medium of refractive index $\mu =1.5$ and thickness $t=2.5\times {10}^{-5}m$ is inserted in front of one of the slits of Youngs double-slit experiment, how much will be the shift in the interference pattern? The distance between the slits is $0.5mm$ and that between slits and screen is$100cm$.

1. $5cm$

2. $2.5cm$

3. $0.25cm$

4. $0.1cm$

Q. An electron beam is being used in YDSE. On increasing kinetic energy of the electrons, fringe width will:

1. Increase
2. Decrease
3. Remain unchanged
4. No interference pattern will be observed on the screen

Q.

In a double-slit experiment, at a certain point on the screen, the path difference between the two interfering waves is $\frac{1}{8}$ of a wavelength. The ratio of the intensity of light at that point to that at the center of a bright fringe is?

1. $0.568$

2. $0.853$

3. $0.672$

4. $0.760$

Q. Laser light of wavelength $630nm$ incident on a pair of slits produces an interference pattern in which the bright fringes are separated by $8.1mm$. A second light produces an interference pattern in which the fringes are separated by $7.2mm$. Then the wavelength of the second light will be

1. $500nm$
2. $560nm$
3. $600nm$
4. $660nm$

Q. In Young's double slit experiment, the two slits are illuminated by light of wavelength $5890\stackrel{\circ }{A}$ and the angular fringe width is ${0.2}^{\circ }$. If the whole apparatus is immersed in water, then the new angular fringe width will be (refractive index of water $=\frac{4}{3}$).

1. ${0.05}^{\circ }$
2. ${0.20}^{\circ }$
3. ${0.35}^{\circ }$
4. ${0.15}^{\circ }$

Q. Monochromatic light from a narrow slit illuminates two narrow slits 0.3 mm apart, producing an interference pattern with bright fringes 1.5 mm apart on a screen 75 cm away. Find the wavelength of the light. Find the fringe width if (a) the distance of the screen is doubled and (b) the separation between the slits is doubled?

1. 600 nm, 3 mm, 0.75 mm
2. 400 nm, 1 mm, 0.5 mm
3. 600 nm, 2 mm, 0.75 mm
4. 400 nm, 1mm, 2 mm

Q. In the figure $S_1$ and $S_2$ are two narrow slits illuminated by light of wavelength ${}^{\prime }{\lambda }^{\prime }$ and they ae in phase. `P' is a point on the screen which corresponds to 4th minimum then the path difference $S_{2}P–S_{1}P$ is equal to

1. $4\lambda$
2. $5\frac{\lambda }{2}$
   
3. $7\frac{\lambda }{2}$
   
4. $2\lambda$

Q. In an interference experiment, third bright fringe is obtained at a point on the screen with a light of $700\text{nm}$. What should be the wavelength of the light in order to obtain $5^{th}$ bright fringe at the same point?

1. $500\text{nm}$
2. $630\text{nm}$
3. $750\text{nm}$
4. $420\text{nm}$

Q. In Young’s double slit experiment, the distance between the slits is 0.2 mm and the distance of the screen from the slits is 2 m. If light of wavelength 500 nm is used, find the number of fringes formed between two points separated by 1 cm on the screen.

1. 1
2. 2
3. 3
4. 4

Q. In Young's double slit experiment, the two slits are illuminated by light of wavelength $5890\stackrel{\circ }{A}$ and the angular fringe width is ${0.2}^{\circ }$. If the whole apparatus is immersed in water, then the new angular fringe width will be (refractive index of water $=\frac{4}{3}$).

1. ${0.05}^{\circ }$
2. ${0.20}^{\circ }$
3. ${0.35}^{\circ }$
4. ${0.15}^{\circ }$

Q. The fringe width changes from 0.24 mm to 0.3 mm when the screen is moved by 20 cm away from the slits separated by 2 mm. calculate the wavelength of light used.

1. 400 nm
2. 500 nm
3. 600 nm
4. 700 nm

Q. In a Lloyd's single mirror experiment, the distance between the slit source and its image is $5mm$. The screen is at a distance of $1\text{m}$ from the source. The fringe width is observed to be $0.1mm$. Then the wavelength of light used is

1. $5460\stackrel{\circ }{A}$
2. $5000\stackrel{\circ }{A}$
3. $6460\stackrel{\circ }{A}$
4. $4000\stackrel{\circ }{A}$

Q. Two slits separated by 0.200 mm are to be sued in Young's double – slit experiment. Immediately behind the slits in a lens of focal length 0.500 m used to form the interference pattern on a screen located in the focal plane of the lens. What is the wavelength of a monochromatic light source used to illuminate the slits if adjacent maxima of the interference pattern are separated by 1.00 mm?

1. 400 nm
2. 500 nm
3. 600 nm
4. 700 nm

Q. Coherent electron beam is being used in YDSE. On increasing accelerating voltage, fringe width will

1. decrease
2. remain unchanged
3. increase
4. may increase or decrease

Q. The Young's double slit experiment is performed with blue light and green light of wavelength $4360\dot{A}$ and $5460\dot{A}$ a respectively. If X is the distance of $4^{th}$ maxima, from the central one, then:

1. $X_{blue}=X_{green}$
2. $X_{blue}>X_{green}$
3. $X_{blue}<X_{green}$
4. $\frac{X_{blue}}{X_{green}}=\frac{5460}{4360}$

Q.

Two coherent light sources S₁ and S₂ (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be

1. 0.015 cm

2. 0.025 cm

3. 0.010 cm

4. 0.030 cm

Q. The distance between two slits is 1.2 mm. If the wavelength of light used is $4800\dot{A}$ and the screen is at a distance of 1 m from the slits, how many fringes are observed on the screen in the space opposite to the slits

1. 1
2. 2
3. 3
4. 8

Q. An electron beam is being used in YDSE. On increasing kinetic energy of the electrons, fringe width will:

1. Increase
2. Decrease
3. Remain unchanged
4. No interference pattern will be observed on the screen

Q. In the double-slit experiment, the distance of the first dark fringe from the central line is 1mm. The distance of the $2^{nd}$ bright fringe from the central line is

1. 6mm
2. 4mm
3. 12mm
4. 16mm

Q. The fringe width changes from 0.24 mm to 0.3 mm when the screen is moved by 20 cm away from the slits separated by 2 mm. calculate the wavelength of light used.

1. 400 nm
2. 500 nm
3. 600 nm
4. 700 nm

Q. In Young's double slit experiment, the two slits are illuminated by light of wavelength $5890\stackrel{\circ }{A}$ and the angular fringe width is ${0.2}^{\circ }$. If the whole apparatus is immersed in water, then the new angular fringe width will be (refractive index of water $=\frac{4}{3}$).

1. ${0.05}^{\circ }$
2. ${0.20}^{\circ }$
3. ${0.35}^{\circ }$
4. ${0.15}^{\circ }$