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प्रश्न
Explain constructive and destructive interference with the help of a diagram?
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उत्तर
Constructive and destructive interference:
- Points, where the crest of one wave coincides with the crest of another wave and where the trough of one wave coincides with the trough of another wave, are points with the maximum displacement. At these points, displacement is twice that for each wave. These are points of constructive interference.
- Points, where the crest of one wave is coincident with the trough of another, are points with zero displacements. These are points of destructive interference.

Interference for waves
संबंधित प्रश्न
Write the important characteristic features by which the interference can be distinguished from the observed diffraction pattern.
When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of ______________ .
A long narrow horizontal slit is paced 1 mm above a horizontal plane mirror. The interference between the light coming directly from the slit and that after reflection is seen on a screen 1.0 m away from the slit. If the mirror reflects only 64% of the light energy falling on it, what will be the ratio of the maximum to the minimum intensity in the interference pattern observed on the screen?
In Young’s double slit experiment, the slits are separated by 0.5 mm and screen is placed 1.0 m away from the slit. It is found that the 5th bright fringe is at a distance of 4.13 mm from the 2nd dark fringe. Find the wavelength of light used.
Why are multiple colours observed over a thin film of oil floating on water? Explain with the help of a diagram.
What are the two methods for obtaining coherent sources in the laboratory?
A double-slit arrangement produces interference fringes for sodium light (λ = 589 nm) that are 0.20° apart. What is the angular fringe separation if the entire arrangement is immersed in water (n = 1.33)?
Why two light sources must be of equal intensity to obtain a well-defined interference pattern?
What is interference?
In a Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance D must be changed to ______.
What is intensity (or) amplitude division?
In Young’s double slit experiment, the slits are 2 mm apart and are illuminated with a mixture of two wavelength λ0 = 750 nm and λ = 900 nm. What is the minimum distance from the common central bright fringe on a screen 2 m from the slits where a bright fringe from one interference pattern coincides with a bright fringe from the other?
The ratio of maximum and minimum intensities in an interference pattern is 36 : 1. What is the ratio of the amplitudes of the two interfering waves?
A graph is plotted between the fringe-width Z and the distance D between the slit and eye-piece, keeping other adjustment same. The correct graph is
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B.![]() |
C.![]() |
D.![]() |
On a rainy day, a small oil film on water shows brilliant colours. This is due to ____________.
Band width for red light of wavelength 6600 Å is 0.42 mm. If red Light is replaced by blue light of wavelength 4400 Å, then the change m bandwidth will be ____________.
Two identical light waves having phase difference 'Φ' propagate in same direction. When they superpose, the intensity of the resultant wave is proportional to ______.
In Young's experiment for the interference of light, the separation between the silts is d and the distance of the screen from the slits is D. If D is increased by 0.6% and d is decreased by 0.2%, then for the light of a given wavelength, which one of the following is true?
"The fringe width ____________."
If the two slits in Young's double slit experiment have width ratio 9 : 1, the ratio of maximum to minimum intensity in the interference pattern is ______.
In the Young's double slit experiment, if the phase difference between the two waves interfering at a point is `phi`, the intensity at that point is proportional to ____________.
If two waves represented by `"y"_1 = 3 "sin" omega "t"` and `"y"_2 = 5 "sin" (omega "t" + pi/3)` interfere at a point, then the amplitude of the resulting wave will be about ____________.
In biprism experiment, if the 5th bright band with wavelength 'λ1' coincides with the 6th dark band with wavelength 'λ2' then the ratio `(lambda_2/lambda_1)` is ______
Light waves from two coherent sources arrive at two points on a screen with a path difference of zero and λ/2. The ratio of the intensities at the points is ______
Young's double slit experiment is performed in water, instead of air, then fringe width ______.
Interference fringes are produced on a screen by using two light sources of intensities I and 9I. The phase difference between the beams is `pi/2` at point P and π at point Q on the screen. The difference between the resultant intensities at point P and Q is ______.
A ray of light AO in a vacuum is incident on a glass slab at an angle of 60° and refracted at an angle of 30° along OB as shown in the figure. The optical path length of the light ray from A to B is ______.

Describe Young's double-slit interference experiment.
With a neat labelled ray diagram explain the use of Fresnel's biprism to obtain two coherent sources.
In biprism experiment the maximum intensity is ‘I0’. If the path difference between the two interfering waves is ‘λ/4’ then intensity at the point on the screen is ______.
`[sin 45^circ = cos 45^circ = 1/sqrt 2]`




