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Teacher’s Lab Experiments

Teacher’s Lab Experiments. Importance, relevance and the level of students’ preparedness, before trying on these experiments. Electron Spin Resonance.

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Teacher’s Lab Experiments

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  1. Teacher’s Lab Experiments Importance, relevance and the level of students’ preparedness, before trying on these experiments.

  2. Electron Spin Resonance In this experiment, a ball with a central rod magnet, rotates with low friction on air cushion and acts as model electron. Two pairs of coils generate a constant magnetic field B0 and an alternating magnetic field B1. The axes of both fields intersect perpendicularly at the centre of the ball. The table is slightly inclined to start the electron gyroscope with an air draught (Magnus effect). If the direct magnetic field B0 acts on the ball, a precision of the magnet axis is observed. Precision frequency increases with the intensity of B0. With the second pair of coils and a pole change over switch (commutator), a supplementary alternating field B1 is generated. If the change of poles occurs at the right phase, the angle between the gyroscope axis and the direction of the direct field is continuously increased, until the magnetic axis of the ball is opposed to the field direction (spin flip).

  3. Price : 5,305.76 CHF • Comments • Expensive for schools to have • Since it is a demonstrative experiment, some schools might like to have it in their Physics lab. • Students need a prior knowledge of • Zeeman effect • Energy quantum • Quantum number • Resonance • G – factor • Lande’ factor

  4. This experiment can be used • To demonstrate the phenomenon of “electron spin resonance”. • Does not offer too much of student participation. • Needs practice to actually demonstrate the phenomenon involved.

  5. Photoelectric effect In this experiment, a photocell is illuminated with monochromatic light of different wavelengths. Planck’s quantum of action, or Planck’s constant ‘h’, is determined from the photoelectric voltages measured.

  6. Price : 6,977.20 CHF • Comments • Pricy indeed, as a school would like to have more than one of the setup. • Beneficial for the students, as they can practice the art of data collection and manipulation. • Students need a prior knowledge of • External photoelectric effect • Work function • Adsorption • Photon Energy

  7. This experiment can be used • To study voltage of the photo cell as a function of the frequency of the irradiated light. • Definitely a good experiment, from the students’ as well as the schools’ points of view.

  8. Cathode Ray Tube In this experiment, cathode rays ( a stream of electrons) are subjected to a magnetic field and the corresponding trace is viewed on a fluorescent screen. This exercise is helpful to study how “Lorentz force” works.

  9. Price : 3,336.80 CHF • Comments • Very good demonstrative experiment. • Can be used to demonstrate so many other phenomenon, like thermionic emission and Lissajous figures. (We tried but could not handle the function generator) • Students need a prior knowledge of • Thermionic emission • Lorentz Force • Magnetic field around a solenoid (coil)

  10. This experiment can be used • To demonstrate phenomenon like • Thermionic emission • Lorentz force • Oscilloscope principals • Wave forms • Lissajous figures (improvisation required) • An useful experiment for students, teachers and schools • Can be improvised to an exercise experiment

  11. Fine Beam Tube(Specific charge of the electron - e/m) In this experiment, electrons are accelerated in an electric field and enter a magnetic field at right angles to the direction of motion. The specific charge of the electron is determined from the accelerating voltage, the magnetic field strength and the radius of the electron orbit.

  12. Price : 7,074.00 CHF • Comments • Relatively expensive. • Certainly a good experiment to have in a well equipped laboratory. • Students need a prior knowledge of • Cathode rays • Lorentz force • Electron in crossed field • Electron mass • Electron charge

  13. This experiment can be used • For the determination of specific charge of the electron (e/m0) from the path of an electron beam in crossed electric and magnetic fields of variable strength.

  14. Electron Diffraction Tube In this experiment, fast electrons are diffracted from a polycrystalline layer of graphite. Interference rings appear on a fluorescent screen. The interplanar spacing in graphite is determined from the diameter of the rings and the accelerating voltage.

  15. Price : 3,985.76 CHF • Comments • Relatively inexpensive. • Not safe for students to try their hands on. • The radius of rings do not match with the voltage most of the times. So the readings are not easily reproducible. • Preparedness of your class in order to make the most of this experiment • Bragg reflection • Debye – Scherrer method • Lattice planes • Graphite structure • Material waves • De – Broglie equation

  16. This experiment can be used • To measure the diameter of the two smallest diffraction rings at different anode voltages. • To calculate the wavelength of the electrons from the anode voltages. • To determine the interplanar spacing of graphite from the relationship between the radius of the diffraction rings and the wavelength

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