College physics experiments include: Young's modulus, Michelson interferometer, holography, diffraction grating, single slit diffraction, photoelectric effect, measuring the refractive index of glass with spectrometer, measuring the base point of lens group, measuring the propagation speed of wave, Millikan oil drop experiment, using analog oscilloscope, measuring giant magnetoresistance, measuring the characteristics of semiconductor electro-optical devices, and equal thickness interference.

1, Young's modulus

Young's modulus is a physical quantity that describes the deformation resistance of solid materials. When a metal wire with a length of L and a cross-sectional area of S is extended by a force F, F/S is called stress, and its physical meaning is the force per unit cross-sectional area of the metal wire; Δ l/l is called strain, and its physical meaning is the elongation corresponding to the unit length of metal wire.

2. Michelson interferometer

Michelson interferometer is a kind of precision optical instrument designed and manufactured by American physicists Michelson and Morley in 188 1, which is used to study the "ether" drift. It uses amplitude division method to generate double beams to realize interference.

3. Equal thickness interference

Equal thickness interference is an interference fringe formed by parallel light incident on the upper and lower surfaces of thin films with uniform thickness and refractive index. The same interference fringes are formed where the film thickness is the same, so it is called equal thickness interference. (Newton's ring and wedge plate interference belong to equal thickness interference. )

4, the use of oscilloscope

The wave device is a narrow electron beam composed of high-speed electrons hitting the screen coated with fluorescent substances, which can produce tiny light spots (this is the working principle of the traditional analog oscilloscope).

5, bridge method to measure resistance

Typical four-line measurement method is adopted. In order to improve the accuracy of measuring resistance (especially low resistance). Program-controlled constant current source, program-controlled preamplifier and A/D converter constitute the main body of the measuring circuit. The central control unit applies constant and high-precision current to the measured external load by controlling the constant current source, and then processes the obtained data (including test voltage, current test current, etc.). ) to obtain the actual resistance value.

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