Question

Two slits separated by a distance of d = 0.11mm are located at a distance of D = 780mm from a screen. The screen is oriented parallel to the plane of the slits. The slits are illuminated by a coherent light source with a wavelength of lambda = 524E-6 mm. The interference pattern shows a peak at the center of the screen (m=0) and then alternating minima and maxima. 1. [1pt] What is the pathlength difference between the two waves from the two slits at the first minimum to the side of the central maximum on the screen?

Answer 1

This is a question based on young's double slit experiment.

so basically we need to find the distance of the first maxima from the central maxima.

In young's double slit experiment,

the distance of the the mth maxima from the central maxima is given by the formula,

where m is the mth order, lambda is the wavelength, D is the distance of the screen from the slits and d is the distance between the slits.so,

y=(1*524*10^-9*0.78)/(0.11*10^-3)

or y=3.71*10^-3 m