3B Scientific, UE5010200-230, Experiment for Atomic Physics: Planck's Constant, 230 V, 50/60 Hz
UE5010200-230 Includes Only:
- 1 Basic apparatus (230 V, 50/60 Hz) with photocell, voltmeter, nano-ammeter, and power supply for light sources
- 5 LEDs in casings with connector leads
- 1 Plug-in power supply, 12 V AC
Features:
In a modified version of a classic set-up, light of known frequency passes through a ring-shaped anode to collide with a cathode, where it causes electrons to be released due to the photo-electric effect. The energy of the electrons can be determined by applying a decelerating voltage, which compensates for the flow of electrons towards the anode until no electrons are flowing. This demonstrates that the cut-off value of the decelerating voltage which corresponds to a current of zero is not dependent on the intensity of the light. The energy of the electrons is therefore similarly independent of intensity. By obtaining the cut-off voltages for light of varying frequency, it is possible to calculate Planck's constant.
