PLANCK’S CONSTANT

Planck’s Constant Apparatus

FIGURE 2-CHARACTERISTIC CURRENT/VOLTAGE CURVE OF THE 6 LED'S

• Determine the wavelength of 6 LED’s using a diffraction grating
• Plot current/voltage curves characteristic of the LED’s (see fig. 2)
• Determine Planck’s constant (see fig. 1)

This simple unit enables the student to perform these classical optical experiments. Six LED’s emit light at different wavelengths. As power is supplied to each LED, light will be emitted when the energy difference between two electronic states in a diode is great enough for an electron transition to release one quantum of light at the wavelength of the LED.

A dual trace oscilloscope can be used to display this characteristic curve. Observing the applied voltage at the “knee” of this curve (see figure 3) for several different LED’s Planck’s constant can be determined within 10%.

Required Accessories 0-6 VAC Power Supply Dual Trace Oscilloscope

TEL 6789

$199.00