Question

5. In a two-slit experiment, the slit separation is 3.00x 10^-5 m. The interference pattern is created on a screen that is 2.00 m away from the slits. If the 7^th bright fringe on the screen is 10.0 cm away, from the central fringe, what is the wavelength of light?

6. A single slit, which is 0.0500 mm wide, is illuminated by light of 550 nm wavelength. What is the angular separation between the first two minima on either side of the central maximum?

Answer 1

5) It is clear that the interference pattern on the screen consists of alternating light and dark bands, running parallel to the slits. The distances of the centers of the various light bands from the centre point are given by

  

where m= 0, 1, 2, 3....

isthe wavelength of light ,

is the distance of the screen from the slit and

is the slit separation distance.

Therefore

6) In single slit experiments the minimum occurs at,

  

where ,

is the wavelength

a is the slit width

Therefore

For the first bottom fringe, ie n=1

Angle will be same for the upper first fringe also

therefore the angular separation is