proper defination of saturation current and stopping potential?
The photo electrons emitted in photoelectric effect from cathode will be gained by anode to which positive potential is applied. If this positive potential is gradually increase photo electrons gained by anode also increases and reaches saturation state.i.,e with further increase of + ve potential to anode there will be no change in photo electric current. This maximum value of current is called "Saturation Current".
Now the potential of anode is to be reversed ( - ve ). If this negative potential applied to anode is gradually increased the number of photoelectrons reached to anode decreases and finally becomes Zero. " This reverse potential ( -ve)applied to anode where the photo electric current is zero is called Stopping Potential".
in the photoelectric effect if we increases the positive potential of the anode the more and more of the electron are emitted by the cathode and current are increases gradually .at the stage come if we increases the positive potetial of the anode the current attain a its maximum value further current are not increases .The maximum value of current is called Saturation current .
if we increases the negative potential of the anode the electron comes from the cathode are repelled by them and the current are decrease gradually and at 0. the potential at which the current is zero is called the stopping potential and cut off potential.