CANA 1F91 Lecture Notes - Diffraction, Photon

A student shines a red laser pointer with a wavelength of 675 nm through a double-slit apparatus in which the two slits are separated by 75.0 µm. He observes the diffraction pattern on the wall 1.50 m away. What is the distance between the central bright fringe and either of the neighbouring bright fringes on the wall? 

A laser beam of unknown wavelength shines through the two slits and produces a diffraction pattern with dark bands at y1 = 21.3 mm, y2 = 64.0 mm, and y3 = 106.7 mm from the center of the central intensity maximum. If the distance between the slits d = 21 µm, and the distance between the slits and the screen is D = 143 cm, what is the wavelength of the laser light used?

A slit 0.937 mm wide is illuminated by light of wavelength 663 nm. We see a diffraction pattern on a screen 2.49 m away. What is the distance in millimeters between the first two diffraction minima on the same side of the central diffraction maximum?