The threshold frequency of molybdenum is 10¹⁵. The yellow light can not cause the ejection of photoelectrons from molybdenum.
The work function of molybdenum is 4.22 eV.
The work function is the minimum energy of the photon that is required for the ejection of electron from the metal surface.
(a) So, energy of photon,
E = hc/y
where,
E is the energy of photon,
h is the Planck's constant,
y is wavelength of the wave,
c is the speed of light,
Or, it can be written as,
E = hv
Where, v is the frequency of the wave,
E is equal to the work function of the metal.
So, the threshold wavelength of molybdenum is,
4.22 × 1.6 × 10⁻¹² = 6.63 × 10⁻³⁴ v
v = 1.01 × 10¹⁵
So, the frequency is about 10¹⁵.
(b) we know,
c/y = v
The wavelength of the yellow light is 560nm.
So,
3×10⁸/560×10⁻⁹ = v
v = 0.53×10¹⁵
This frequency is less than the threshold frequency, so, photoelectric effect will not be observed.
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