Diffraction pattern intensity measurements in the introductory college physics laboratory using microcomputers

Measurement of the intensity variations in a single slit diffraction pattern formed by a laser beam is made by means of a photoresistor detector interfaced with an Apple II‐plus microcomputer through the paddle (game controller) connection. The computer programs, written in BASIC and assembly language, enable the student to (1) determine quantitatively the intensity of the maxima and minima; (2) see the intensity pattern as the data is acquired; (3) obtain a hard copy of the intensity plot observed on the screen monitor; and (4) compare the experimental and theoretical intensity patterns.