Photo electric effect...

In an experiment to study photoelectricity( cathode ray tube?..)..connected to a battery....suppose we consider these cases..
CASE 1
--a particular metallic emmitter is taken( work function = 4 ev)..and a suitable frequency of light is made to fall( energy = 6 ev)...intensity being constant...(say 3 electrons r emmitted)...
---ENERGY associated with electrons r 2 ev 1.8 ev 1.9 ev(theoritically all 3 will have energy= 2ev)..when no negative potential is applied....now
CASE 2
----keeping all constants but the potential..wch is made negative(say 1 volt)..now the energy of electrons changes to
--1ev , 0.8ev, 0.9 ev..
-------now my question is..whether the current in the circuit decreases ?..if so how and is it measurable or too negligible?..


---if the answer is yes then suppose the frequency is incresed( others remain as constants)...does the current in the circuit increases?..(..potential is constant at 1 volt).

that is if frequency is incresed to say 12 ev consequently the energies of electrons also increase but negative potential is same....does it effect the current....

i have referred many text books wch say that the magnitude of photocurrent is independent of frequency once it is above threshold level...
plz clarify...
thanx..