Question

In the double slit interference experiment, if the distance between the monochrome light source S and the two slits S1 and S2 is equal, the central bright stripe on the observation screen is located at the O position in the figure. Now, the light source S is moved downward to the S’position in the sketch. Which of the statements below is right?


A-The central fringes move downward and the stripe spacing remains unchanged.

B-The central fringes move upward and the stripe spacing remains unchanged.

C-The central fringes move downward and the stripe spacing increases.

D-The central fringes move upward and the stripe spacing increases.

Answer 1

Answer:

B

Explanation:

The central fringes will have moved upward as the direction of light source has changed and went downward. Tis can be seen in the diagram. The stripe spacing just depends upon the wavelength and the length of the slits which is constant in both the cases so stripe spacing remains unchanged.

Answer 2

Answer:

Now, the light source S is moved downward to the S'position in the sketch. Which of the statements below is right? A-The central fringes move downward and the stripe spacing remains unchanged