List of top Physics Questions on wave interference

Two harmonic waves moving in the same direction superimpose to form a wave $ x = a \cos(1.5t) \cos(50.5t) $ where $ t $ is in seconds. Find the period with which they beat (close to the nearest integer):
A thin transparent film with refractive index 1.4 is held on a circular ring of radius 1.8 cm. The fluid in the film evaporates such that transmission through the film at wavelength 560 nm goes to a minimum every 12 seconds. Assuming that the film is flat on its two sides, the rate of evaporation is:
The Young's double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference patterns. The least number of the bright fringes of 480 nm light that are required for the first coincidence with the bright fringes formed by 600 nm light is:
Assertion (A): When two waves of equal amplitude and a phase difference of \( \frac{\pi}{2} \) interfere, the resulting intensity is equal to the intensity of one wave. Reason (R): In interference, the resultant intensity is always the sum of individual intensities if the phase difference is non-zero.
For an amplitude modulated wave the minimum amplitude is 3V, while the modulation index is 60%. The maximum amplitude of the modulated wave is

A ray of light of intensity I is incident on a parallel glass slab at point A as shown in diagram. It undergoes partial reflection and refraction. At each reflection, 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio of Imax and Imin is: 

Calculate the wavelength of light used in an interference experiment from the following data: Fringe width = 0.03cm. Distance between the slits and eyepiece through which the interference pattern is observed is 1m. Distance between the images of the virtual source when a convex lens of focal length 16cm is used at a distance of 80cm from the eyepiece is 0.8cm.

There are two sources kept at distances 2λ. A large screen is perpendicular to the line joining the sources. Number of maxima on the screen in this case is (λ= wavelength of light) 

A ray of light of intensity I is incident on a parallel glass slab at point A as shown in the diagram. It undergoes partial reflection and refraction. At each reflection, 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio of Imax and Imin is: 

In Young’s double–slit experiment, the intensity of light at a point on the screen where the path difference is Kλ is K (λ being the wavelength). The intensity at a point where the path difference is λ/4 will be:

In Young's double-slit experiment, the 10th-order maximum is obtained at the point of observation in the interference pattern for \( \lambda = 7000 \, \text{Ã} \). If the source is replaced by another one of wavelength 5000 Å, then the order of maximum at the same point will be â

A mica slit of thickness t and refractive index \( \mu \) is introduced in the ray from the first source \( S_1 \). By how much distance of fringes pattern will be displaced?
A wave y=a(ω t-kx) on a string meets with another wave producing a node at x=0. Then the equation of the unknown wave is