Question

1. What is the condition for light in order to make interference pattern from Young-double slit?
2. How do you make single source to make a source for young double-slit experiment?
3. What happen if you use electron instead of light, what pattern you expect to see, and why?
4. What are the parameters that can affect the interference pattern (mention at least 3)

Answer 1

(a) To make interference pattern, the light sources must be identical, i.e., must have same wavelength, frequency and constant phase difference between them. In one word, the light sources must be coherent sources.

(b) Light coming from the single source is to be incident on a double - slit to make two coherent light sources, so that they can make interference pattern.

(c) Electrons will also make consecutive bright and dark interference pattern as light, since electrons have both wave nature and particle nature. For having a wave nature, electrons can diffract through the edges of the slits and will interfere each other to make a similer pattern as photons ( light ) do.

(d) Three factors, that affect interference pattern are :

<1> Seperation between the slits

<2> Wavelength of the light ( or any other wave ) used

<3> Distance between the slits and the screen on which the pattern is being observed.