Moderate

In YDSE, if we use white light in place of monochromatic light, then the:

Correct answer: A. Centre will be bright and red color will be far from it

  • A. Centre will be bright and red color will be far from it
  • B. Centre will be bright and blue color will be far from it.
  • C. Centre will be dark and red color will be to it
  • D. Centre will be dark and blue color will be to it

Explanation

When we use white light in place of monochromatic light then only the central fringe looks white and other fringes of different colors are observed. The difference in path lengths, being zero at the center gives zero phase difference at the center for all wavelengths hence making the center fringe white. It is because the central fringe for all colors is formed at the center point so it becomes white after mixing up. As fringes of other colors fall at different places we see fringes of all colors on the central bright fringe. At other different points on the screen, the phase difference is given by ϕ=kΔx=2π/ λΔx where Δx is the difference in path lengths. Since λ is different for different colors, the fringe width will be different for each color and hence all other fringes will be colored. The red color will be observed further away from it because it has a shorter wavelength.

Last updated

About Optics

Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.

Practise Optics

665 free Optics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Exams that ask Physics questions like this

Physics is on 7 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

Related questions