A clean potassium surface is illuminated successively by two beams of monochromatic light
PHYSICS · Subjective · CBSE · Physics · Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
Problem
A clean potassium surface is illuminated successively by two beams of monochromatic light, beam X and beam Y. Both beams have the same frequency ν (with ν>ν0 for potassium) but different intensities such that the intensity of beam X is three times that of beam Y.
(i) Sketch on the same set of axes the expected photocurrent–voltage (I–V) characteristics for the two beams and label the curves clearly.
(ii) Identify which curve corresponds to the higher-intensity beam and justify your answer.
(iii) Explain why the stopping potential is the same for both beams even though their intensities differ.
(iv) State two factors, other than intensity and frequency, that could affect the exact numerical value of the saturation current observed in an experiment.