question_answer

The graph of Fig. variation of photo-electric current with collector plate potential for different frequencies of incident radiations. (i) Which physical parameter is kept constant for the three curves? (ii) Which frequency \[\text{(}{{\text{v}}_{\text{1}}}\text{,}{{\text{v}}_{\text{2}}}\text{or }{{\text{v}}_{3}}\text{)}\] is the highest?                             

Answer:

                (i) Intensity has been kept constant because the saturation current is same for three different frequencies of incident radiation. (ii) As stopping potential is highest for the radiation of frequency\[{{v}_{1}}\], so frequency \[{{v}_{1}}\] is highest.