In a Frank-Hertz experiment, an electron of energy 5.6 eV passes through mercury vapour and emerges with an energy 0.7 eV . The minimum wavelength of photons emitted by mercury atoms is close to :
220 nm
250 nm
1700 nm
2020 nm
Frank Hertz Experiment -
Frank and Hertz had proposed that the 4.9 V characteristic of their experiments was due to ionization of mercury atoms by collisions with the flying electrons emitted at the cathode.
- wherein

220 nm
Option 2)250 nm
Option 3)1700 nm
Option 4)2020 nm
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