When two waves going in the same direction have the same phase or phase difference, constructive interference occurs and they give a bright fringe or zone. If they are of opposite phases, they result in destructive interference and cause darkness. The same event occurs for waves reflected from the upper a lower layer of the oil films

For some films (which are not uniform), the thickness might be equal to or an integral multiple of a certain wavelength present (depending on the thicknesses),...

If the monochromatic source of light in Young's Double Slit experiment is replaced by a white light source, then we can obtain colored fringes due to the overlapping of the components of the white light. The central maxima will appear white because no overlapping occurs there rest fringes are colored. As the fringe width for violet colour light is least and that of red light maximum first minima for violet light will come first and the fringe will appear red there. Slightly farther away where...

If a glass plate is used to cover both the slits in Young's Double Slit Experiment, the speed of light passing through the slit decreases. And, we knowλ = v / f. Since the frequency of light remains constant, the wavelength decreases with the decrease in the velocity of sound.
We also know that the fringe width is given by

β =λD/d
where,
D= distance between slit and screen
d= slit width

Since D and d remain constant in the above relation, fringe width is directly proportional to the wavelength of...

If one of the slits of the YDSE is immersed in water, it will take more time to travel the same distance. This means, at the same time, the light through water will travel less distance than from the other slit.

We know that the central bright fringe is formed at the point where the path difference will be zero, i.e. the light from both the slits will cover the same distance. In order to have zero path difference, the central fringe should shift to the side of the water by a distance ofΔx = D(...

In interference, the amplitude of the central bright fringe is double the amplitude of light given by the two coherent sources.
we know, intensity is directly proportional to the square of the amplitude of light.

i.e. Iα A²

So, the intensity of central bright fringe is four times the intensity of light passing through each slit.
i.e. Intensity of light of central bright fringe = 4 X intensity of light through each slit.

Hence, when one slit is covered in YDSE, the central bright fringe will...