1. The problem statement, all variables and given/known data Why does the photoelectric current I not rise vertically up to its maximum value when the appled potential difference is slightly more positive that the stopping potential? 2. Relevant equations 3. The attempt at a solution Simply because,the speed of the photoelectrons also depend on the potential difference they are passing through[apart from the incident ray intensity].As they move their KE becomes converted into PE.As you vary the voltage,the current should vary accordingly... I do not find any more good reasoning behand this...Can anyone please check?