United Scientific™ Planck's Constant Apparatus

Description

Apparatus that measures Planck’s constant and estimates the work function of cesium.

• Compact, easy-to-use apparatus. Accurate results with less than 5% error.
• Measures Planck's constant and estimates the work function of cesium.
• The Planck's Constant Apparatus is a compact unit containing an enclosed vacuum photocell with an attachment for illuminating light sources, a high stability power supply for applying a variable stopping voltage to the cell and a nanoammeter for measuring the resulting photocurrents.
• Light from five interchangeable narrow spectrum LEDs is applied to the photocell from a second integrated high stability power supply via an enclosed fiber optic connecting cable that plugs into the photocell enclosure so that the ambient illumination is excluded.
• A maximum energy of the photons from each of the five LEDs in turn is measured by determining the stopping voltage for which the photocurrent becomes zero.
• This occurs for the peak wavelength of each LED.
• Results are evaluated by combining the wavelength and energies to allow a value for Planck's constant to be found.
• The work function of the photocell cathode material can also be estimated.
• This can be performed graphically, analytically, or using the included Microsoft Excel™ spreadsheet.
• Planck's Constant Apparatus Specifications:
  • Photocathode Material: Cesium (Cs)
  • Voltmeter Display: 3.5 Digit, LCD, precision 0.5% (typical).
  • Ammeter Display: 3.5 Digit, LCD, precision 1% (typical).
  • Dimensions: 28 x 12 x 16 cm
  • Weight: Approx. 1 kg

Specifications

• Product Type: Planck's Constant Apparatus

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