The manual was prepared at the Department of General Physics of the Faculty of Physics of Voronezh State University . Recommended for students of 2nd year d/o and 3rd year in/o Faculty of Physics. Brief theoretical information on light interference when reflected from thin plates and films, on equal slope bands and equal thickness bands. is given. Descriptions of three laboratory works are given: Interference of equal slope bands. Determination of the wavelength of laser radiation and the order of interference; - Determination of the wavelength of light using Newton's rings; - Spectroscopic study of the phenomenon of chromatic polarization of light