## Experimental determination of wavelength/energy

$E=hv$

905022356
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Joined: Mon Oct 02, 2017 7:19 am

### Experimental determination of wavelength/energy

In order to find E we need v, and in order to find v we need E for E=hv. So, how are either E or v experimentally determined?

Hannah Guo 3D
Posts: 56
Joined: Fri Sep 29, 2017 7:06 am

### Re: Experimental determination of wavelength/energy

When a photon hits a metal surface with high enough energy, the metal surface will emit an electron, which is then detected and calibrated for its energy. The scientist can calculate the energy (E) of the photon from the electron's kinetic energy and the thermal energy released in the air. When the electron hits the detector, the detector goes off, so scientists can record the time that the electron travels from the metal plate to the detector in order to calculate the frequency (v) of the electron. Through experiments, scientist found that the energy and the frequency have a positive correlation. When the frequency of the wave increases, it's delivering more energy. The scientists measure multiple sets of the values of frequency and energy in order to find out the Plank's Constant.