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5435 Planck's Constant
5435 Planck's Constant
5435 Planck's Constant
5435 Planck's Constant

5435 Planck's Constant

Regular price $935.00 $0.00 Unit price per

Photoelectric effect - Planck's Constant

Thanks to this apparatus you are allowed to study photoelectric effect, this instrument is a good starting point to study quantum mechanics. It is basically composed of two parts: a phototube and a control unit (in which is built-in a voltmeter and a nanometer). Three LEDs, with wavelength known, are supplied: they are used as monochromatic light sources. The light intensity could be varied from 0 to 100%.
The photoelectric effect or photoemission is the production of electrons or other free carriers when light is shone onto a material.
You will be able to check the relation between the energy of the emitted electrons and the wavelength of the incident radiation: you will be able to calculate which is the value of the Planck constant using Einstein notion regarding photoelectric effect.


Technical data

  • Power supply: 24V DC
  • - Voltmeter 4 digits, sensibility < 2mV
  • - Ammeter 4 digits, sensibility < 5nA
  • - Button to cut off current
  • - LED light adjustment 0-100%
  • - Anodic tension adjustment
  • - Three LEDs (red, green, blu)
  • Dimensions and weight:
  • - Control station 19x13,5x6cm weight 370g
  • - Phototube base 13x18x15,5cm weight 560g

How to use it
Historical notes on the nature of light
Electromagnetic waves
Intensity of electromagnetic waves
Photoelectric effect
Photoelectric cell
Work function
Threshold frequency
Characteristic graphic of a photocell
Stopping potential
Kinetic energy of electrons doesn’t depend on radiation intensity
The number of emitted electrons depends on radiation intensity
Einstein quantum theory
How Einstein quantum theory explains events
How to value threshold frequency
How to measure Planck constant


  • 3 LEDs (green, red and blue)
  • 1 Base with phototube
  • 1 Unit control
  • 1 Power supply

Dimensions and weight:
- Control station 19x13,5x6cm weight 370g
- Phototube base 13x18x15,5cm weight 560g