Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57V The th…

Question

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57V The threshold frequency of the material is

Accepted Answer

Correct answer: C. (c) For hydrogen atom, E_n=- 13.62 eV For ground state, n=1n E_1=- 13.61^2=-13.6eV For first excited state, n=2 ∴E_2=- 13.62^2=-3.4eV The energy of the emitted photon when an electron jumps from first excited state to ground state is h =E_2-E_1=-3.4 eV-(-13.6 eV)=10.2eV Maximum kinetic energy, K_ max=eV_s=e 3.57V=3.57eV According to Einstein’s photoelectric equation K_ max=h - _0 where _0 is the work function and h is the incident energy _0=h -K_ max=10.2 eV-3.57 eV=6.63eV Threshold frequency _0= _0h= 6.63 1.6 10^-19J6.63 10^-34 Js =1.6 10^15Hz

$Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V The threshold frequency of the material is$

Solution

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