dear student,
The photoelectric current is directly proportional to the intensity of the light used, above a minimum value of frequency called the threshold frequency. The saturation current depends on the intensity for a known value of frequency.
Keeping potential of collector fixed note the value of current in the circuit for different intensity of light. A graph between intensity of light and photoelectric current is found to be a straight line indicating that the photoelectric current is directly proportional to the intensity of incident radiation.
thanks and regards...