Determination of the Planck constant by experiment!
Frequency / wavelength conversion
Excellent illustration of the light-matter interaction
This model allows students to observe and quantify the interaction between light and matter and to find the formula governing these interactions: ∆E=hv .
It is composed of 6 electroluminescent diodes illuminating in different wavelengths and distributed over the entire visible spectrum, from purple to red.
A rotary switch selects the LED studied and a potentiometer to vary the DC voltage applied at the input.
Two pairs of safety banana sockets connect the device to an ammeter and a voltmeter to measure the current flowing through the LED and the voltage across it.
By precisely determining the threshold voltage of each of the LEDs, the graphical representation of E = f (v) makes it possible to find the Planck h constant with precision and to demonstrate the relation ∆E = hvTechnical characteristics:

• Power supply: 12 V continuous by 2 safety banana sockets
  
• Dimensions: 150 x 100 x 50 mm approximately
  
• Adjustable tilt stand