1. The problem statement, all variables and given/known data In photoelectric effect I-V graphs, for the same intensity but with different light frequencies (f2>f1), the I-V graph has the same max photocurrent but |Vs2| > |Vs1|. If we concentrate between the cutoff and the saturation regions of the I-V graph, we can see that at any given applied voltage, the photocurrent from the case with light freq f2 is higher than that with f1. Seems the saying increase freq only increases max KE but not the photocurrent cannot explain this observation. 2. Relevant equations 3. The attempt at a solution I know that there are lost of discussions in this and other forums about frequency only increase KE of liberated electrons but not the photocurrent. However, it seems to me that they are talking about the max photocurrent, i.e. the saturation region of the I-V graph but not the "linear" region of the I-V graph. Could the photocurrent for f2 higher than f1 due to the fact that space-charge still exist in this region and therefore the probability of an electron arriving at anode increases with increased KE (specially when the applied voltage is negative)?