# YDSE Problems I

## Trending Questions

**Q.**In YDSE d=2mm D=2m wavelength=500nm.Intensity of 2 slits are I and 9I then find intensity at y=1/6mm.

**Q.**

In a Young’s double-slit experiment, the path difference, at a certain point on the screen between two interfering waves is ${(1/8)}^{th}$ of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to

$0.74$

$0.80$

$0.85$

$0.94$

**Q.**The relative permittivity of distilled water is 81. The velocity of light in it will be :

(Given μr=1)

- 4.33×107 m/s
- 3.33×107 m/s
- 5.33×107 m/s
- 2.33×107 m/s

**Q.**In an interference experiment, the ratio of amplitudes of coherent waves is a1a2=13. The ratio of maximum and minimum intensities of fringes will be

- 4
- 2
- 9
- 18

**Q.**In double-slit experiment using light of wavelength 600 nm, the angular width of a fringe formed on a distant screen is 0.1°. What is the spacing between the two slits?

**Q.**White light is incident normally on a glass plate (in air) of thickness 500 nm and refractive index of 1.5. The wavelength (in nm) in the visible region (400 nm-700 nm) that is strongly reflected by the plate is

- 450
- 600
- 400
- 500

**Q.**In the Young's double slit experiment, the distance between the slits varies in time as d(t)=d0+a0 sinωt; where d0, ω and a0 are constants. The difference between the largest fringe width and the smallest fringe width, obtained over time, is given as :

- 2λD(d0)(d20−a20)
- λDd20a0
- λDd0+a0
- 2λDa0(d20−a20)

**Q.**

In an interference arrangement similar to Youngs double slit experiment, the slits S_{1} and S_{2} are illuminated with coherent microwave sources each of frequency 10^{6} Hz. The sources are synchronized to have zero phase difference. The slits are separated by distance d = 150 m. The intensity I(θ)is measured as a function of q, where q is defined as shown. If I_{0} is maximum intensity, then I(θ) for 0≤θ≤90° is given by

**Q.**

An optical fibre (μ=1.72) is surrounded by a glass coating (μ=1.50). Find the critical angle for total internal reflection at the fibre-glass interface.

**Q.**A parallel beam of diameter d is incident on the air-glass interface, as shown in figure. The diameter of the refracted light beam is

(d=3 mm, θ=45∘ and nglassnair=32)

- √12 mm
- √14 mm
- √6 mm
- 4.5 mm

**Q.**3. Width of the fringes is equal ininterference. In diffraction they are neverequal. IN DIFFRACTION WIDTH OF MAXIMA AND MINIMA IS SAME SO WHY IT SAYS THEY ARE NEVER EQUAL?

**Q.**Two coherent source whose intensity ratio is 81:1 produce interference frimges. Calculate the ratio of intensity of maxima and minima in the fringe system

**Q.**

In Youngs double slit experiment, a third slit is made in between the double slits. Then,

Fringes of unequal width are formed.

Contrast between bright and dark fringes is reduced.

Intensity of fringes totally disappears.

Only bright light is observed on the screen.

**Q.**A simply supported beam has an effective span of 20 m. The limiting ratio of span to effective depth as per IS 456: 2000 is

**Q.**

In youngs double slit experiment, the ratio of intensities of bright and dark bands is $16$ which means:

The ratio of their amplitude is$5$.

Intensities of individual sources are $25$ and$9$ units respectively.

The ratio of their amplitudes is $4$.

Intensities of individual sources are $4$ and $3$ units respectively.

**Q.**

In a young's double slit experiment, two narrow vertical slits placed 0.800 mm apart are illuminated by the same source of yelow light of wavelength 589 nm. How far are the adjacent bright bands in the interference pattern observed on a screen 2.00 m away?

**Q.**Two trees are at distance of 3.14 m from each other. What should be the maximum distance of an observer from tree to see them separately. 1. 21.6 km 2. 10.8 km 3. 15 km 4. 25.2 km

**Q.**In young's double slit experiment the fringe width with light of wave length 6000 A is found to be 4.0mm. What will be the fringe width if light of wavelength 4800 A is used?

- 4.8mm
- 2.8mm

- 3.2mm

- 4.0mm

**Q.**In the Young's double slit experiment shown in the figure, the medium between slit plane and the screen has refractive index varying with time as n=n0+kt, then

- The y co-ordinates of central maximum is Dsinϕn0+kt.
- Velocity of central maximum as a function of time is −kDcosϕ(n0+kt)2.
- If a glass plate of small thickness p is placed in front of S1, then to form central maximum at O, refractive index of glass should vary as n0+kt+dsinϕp.
- If a glass plate of small thickness p is placed in front of S1, then to form central maxima at O, refractive index of glass should vary as n0+kt+dcosϕp

**Q.**

In a Young’s double slit experiment the slit separation is 0.5 m from the slits. For a monochromatic light of wavelength 500 nm, the distance of 3rd^{ }maxima from 2nd minima on the other side is

22.5 mm

2.75 mm

2.25 mm

Question is incorrect

**Q.**How to obtain maixma and minima in single slit diffraction and path difference?

**Q.**The ratio of maximum intensity and minimum intensity obtained in the interference of waves emitted by two coherent sources is 121 : 81. The ratio of amplitude of two coherent sources will be

- 1 : 10
- 10 : 1
- 81 : 121
- 121 : 81

**Q.**Q.13 When a metallic surface is illuminated with radiation of wavelength lamda , the stopping potential is V .if same surface is illuminated with radiation of wavelength 2 lamda , the stopping potential is V/4. the threshold wavelength for the metallic surface is

**Q.**ntIn a single slit diffraction of light of wavelengths by a slit of width e, the size of the central maximum on a screen at a distance b is?n

**Q.**In a Young's double slit experiment, d=1 mm, λ=6000 ˚A and D=1 m. The two slits have equal intensity. The minimum distance between two points on the screen, having 75% intensity of the maximum intensity is,

- 0.45 mm
- 0.40 mm
- 0.30 mm
- 0.20 mm

**Q.**

In a Youngs double slit experiment, constructive interference is produced at a certain point P. The intensities of light at P due to the individual sources are $4$ and $9$ units. The resultant intensity at point P will be

$13units$

$25units$

$\sqrt{97}units$

$5units$

**Q.**A single slit is illuminated with a parallel beam of light of wavelength 6000 A∘ and a diffraction pattern is obtained on a screen 1.2 m away from the slit. Distance between position of zero intensity on both side of central maxima is found to be 3.5 mm, then width of slit is

- 0.4 mm
- 1.2 mm
- 0.7 mm
- 0.8 mm

**Q.**A ray of light falls on a transparent sphere with its centre at C, as shown in the figure. The ray emerges from the sphere parallel to the line AB. Then, the refractive index of the sphere is

- √2
- √3
- 32
- 12

**Q.**

Two narrowsslits emitting light in phase are separated by adistance of 1.0 cm. The wavelength of the light is 5.0×10−7 m. The interference pattern in observed on a screen placed at a distance of 1.0 m. (a) Find the separation between the consecutive maxima. can you expect to distingish between these maxima? (b) Find the separation between the sources which will give a separation of 1.0 mm between the cnsecutive maxima.

**Q.**

Two coherent point sources S1 and S2 vibrating in phase emit light of wavelength λ0 the separation between the sources is 2λ. consider a line passing thrrough S2 and perpendicular to the lineS1S2 What is the smallest distance from S2 where is the smallest distance from S2 where a minimum of intensity occurs?