Home
Class 12
PHYSICS
For the sustained interference of light,...

For the sustained interference of light, the necessary condition is that the two sources should

A

have constant phase difference

B

be narrow

C

be close to each other

D

of same amplitude

Text Solution

Verified by Experts

The correct Answer is:
A
Sustained interference means a interference pattern (arrangement of fringes) can not be change with time. It is only possible when the phase difference between waves at a point does not change with time.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • WAVE OPTICS

    ALLEN |Exercise Exercise 2 (Brain Teasures)|22 Videos

  • WAVE OPTICS

    ALLEN |Exercise Exercise 3 (Miscellaneous type Questions)|27 Videos

  • WAVE OPTICS

    ALLEN |Exercise Example 15|1 Videos

  • UNIT & DIMENSIONS, BASIC MATHS AND VECTOR

    ALLEN |Exercise Exercise (J-A)|7 Videos

Similar Questions

Explore conceptually related problems

When interference of light takes place

Diffraction and interference of light refers to -

Write the necessary condition for water drop to stick to glass .

What are the necessary conditions for any system to be aromatic ?

Thin films, including soap bubbles and oil slicks, show patterns of alternating dark and bright regions resulting from interference among the reflected light waves. If two waves are in phase their crest and troughs will coincide. The interference will be constructive and the aplitude of the resultant wave will be greater than the amplitude of either constituent wave. if the two waves are out of phase, the crests of one wave will coincide with the troughs of the other wave. The interference will be destructive and the amplitude of the resultant wave will be less than that of either constituent wave. at the interface between two transparent media some light is reflected and some light is refracted. * When incident light, reaches the surface at point a, some of the light is reflected as ray R_(a) and and some is refracted following the path ab to the back of the film. *At point b some of the light is refracted out of the film and part is reflected back refracted out of the fiml as ray R_(c) . R_(a) and R_(c) are parallel. However, R_(c) has travelled the extra distance within the film of abc. if the angle of incidence is small then abc is approximately twice the film's thickness. if R_(a) and R_(c) are in phase they will undergo constructive interference and the region ac will be bright if R_(a) and R_(c) are out of phase, they will undergo destructive interference. * Refraction at an interface never changes the phase of the wave. * For reflection at the interface between two media 1 and 2, if n_(1)ltn_(2) the reflected wave will change phase by pi . if n_(1)gtn_(2) the reflected wave will not undergo a phase change. for reference n_(air)=1.00 * if the waves are in phase after refection at all interfaces, then the effects of path length in the film are Constructive interference occur when (n= refractive index) 2t=mlamda//n" "m=0,1,2,3... .. Destructive interference occurs when 2t=(m+1//2)lamda//n" "m=0,1,2,3... Q. A 600 nm light is perpendicularly incident on a soap film suspended in air. The film is 1.00 mum thick with n=1.35. Which statement most accurately describes the interference of the light reflected by the two surfaces of the film?

State two conditions to obtain sustained interference of light. In young's double slit experiment, using light of wavelength 400 nm, interference fringes of width X are obtained. The wavelength of light is increased to 600 nm and the separation between the slits is halved. if one wants the observed fringe width on the screen to be the same in the two cases, find the ratio of the distance between the screen and the plane of the slits in the two arrangements.

A vessel is fully filled with liquid having refreactive index 5/3 . At the bottom of the vessel a point-like source of light is kept. An observer looks at the source of light from the top. Now, an opaque circular disc is kept on the surface of the water in such a way that its centre just rests above the light source. Now liquid is taken out from the bottom gradually. Calculate the maximum height ofthe liquid to be kept so that light source cannot be seen from outside. (Radius of the disc is 1 cm.)

For the given statements identify the necessary and sufficient conditions. t: If you drive over 80 km per hour, then you will get a fine.

For the given statements identify the necessary and sufficient conditions t: If you drive over 80 km per hour, then you will get a fine.

The intensity variation in the interference pattern obtained with the help of two coherent source is 5% of the average intensity find out the ratio of intensties of two sources.

Home
Profile