Physics 165 Laboratory, Fall 2000

Tuesdays, 1:30-4:00 pm, Olin 203

Instructor: G. Holzwarth, Olin 215, gholz@wfu.edu, extension 5533

TA: David B. Hill

Experiments

1. Statistical treatment of errors: review of mean, standard deviation, standard deviation of the mean. Least-squares fitting of a model(linear or nonlinear) to experimental data, using Solver.

2. e/m for the electron. In this experiment, an electron gun generates a beam of electrons. The beam is deflected by a transverse electric field, a transverse magnetic field, or both. When the forces exerted by the two fields cancel, the beam travels undeflected; this is the experimental design used by Thomson to measure e/m.

3. Charge e of the electron (2 periods). This is the "falling oil drop experiment" used by Robert Millikan to measure e..

4. The Photoelectric Effect. Light of different wavelengths falls on a metallic surface, releasing electons. We measure the kinetic energy of the released electrons. From these measurements and Einstein's Photoelectric equation, , Planck's constant h can be determined.

5. Nuclear Magnetic Resonance. Using the TeachSpin pulsed nmr spectrometer, we will observe a free-induction decay and measure T1 and T2, the longitudinal and transverse relaxation times.

6. Quantization of electronic energy levels of atoms(Franck-Hertz). Using a beam of low-energy electrons, this experiment shows that electronic energy levels of mercury atoms are quantized.

7. Wavelength of the electron. Electrons are accelerated by an electron gun, then scattered from a carbon-film lattice, which acts as a grating. By measuring the scattering angles for constructive interference, we can test deBroglie's hypothesis that the wavelength lambda=h/p, where h is Planck's constant and p is the momentum.

8. Bragg's Law (with microwaves). To test Bragg's Law quantitatively, we send 2.85 cm microwaves through a "crystal" of steel balls packed in an array with 3.1 cm spacing, and look for constructive interference in the scattered microwaves.

9. X-ray emission spectrum of Cu. When 30 KeV electrons slam into a copper anode, x-rays are released. We use an NaCl crystal "grating" and Geiger-Muller counter, and Bragg's Law, to determine the spectrum of the emitted x-rays.

10. Hall Effect. We assemble a simple Hall probe to measure the strength of a magnetic field.

11. Absorption of x-rays and gamma rays. 10 KeV x-rays, as well as 120 KeV, 1170 KeV, and 1330 KeV gamma rays, are send through Aluminum and Lead absorbers of different thicknesses. This lets us measure the photon cross-sections of these two elements at different photon energies.

Reports for experimental work completed in week w are due before lab begins in week w+1. Reports turned in after that time will be docked 5 points. Place completed reports in the marked drawer in Room 203, please. They will be returned in the drawer below. Based on WordFile 165_Schedule_00.doc