0

We were taught that the intensity of light is equal to the rate of flow of photons per unit area times the energy of each photon(planck’s constant times its frequency) then would that mean the saturation current is dependent on the frequency of light as well as photon flux and/or the intensity?

user10738905
  • 11

1 Answers1

0

The following makes gross simplifications which turn out to be wrong, for details see Pieter's answer on a similar question

Under the assumption that all electrons leave the metal with $KE = hf - W$ we would have:

  1. No photo current if $hf \le W$ regardless of intensity.
  2. For fixed $f$ so that $hf > W$, the saturation photo current will increase if intensity is increased because increased intensity -> more photons hitting the cathode in unit time -> more electrons are ejected in unit time.
  3. If you somehow manage to maintain constant intensity while varying frequency: intensity of monochromatic light can be written as $I_{\text{ph}} = \frac{Nhf}{t}$. If you increase $f$, the quantity $\frac{N}{t}$ must decrease to have the same intensity. So less photons strike the cathode in unit time -> less photo current.
Jasper
  • 1,798