Given below are two statements:
Statement I : In a Young’s double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits
Statement II : In a Young’s double slit experiment, the angular separation of fringes will increase when monochromatic source is replaced by another monochromatic source of higher wavelength
In the light of the above statements, choose the correct answer from the options given below:

Question

Given below are two statements:

Statement I : In a Young’s double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits

Statement II : In a Young’s double slit experiment, the angular separation of fringes will increase when monochromatic source is replaced by another monochromatic source of higher wavelength

In the light of the above statements, choose the correct answer from the options given below:

G1 Physics · Accepted Answer

In Young's double-slit experiment, the angular fringe separation is Δθ = λ/d, where λ is wavelength and d is slit separation. It is independent of the distance D between the slits and the screen. Therefore moving the screen farther away does not change the angular separation. Statement I is false. If the wavelength is increased while d remains unchanged, Δθ = λ/d increases. Therefore Statement II is true. Correct option: C.