Question
A monochromatic light source of frequency v illuminates a metallic surface and ejects photoelectrons. The photoelectrons having maximum energy are just able to ionize the hydrogen atom in ground state. When the whole experiment is repeated with an incident radiation of frequency , the photoelectrons so emitted are able to excite the hydrogen atom beam which then emits a radiation of wavelength 1215Å. Find the work function of the metal and the frequency v.

None of these



diffcult
Solution
According to Einstein’s photoelectric equation, we have
And
Dividing, we get
.
On solving :
.
= 6.875 eV.
From eq. (i), we have
.
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