Question

In an experiment to test the photoelectric effect, Divya shines a 450 nm blue laser at a sodium target. This produces a current I in a circuit she is using to detect the electrons emitted. Which of the following changes in her experimental setup would double the current in the circuit to 2I ?
(The work function of sodium is approximately 2.36 eV.)

Double the intensity of the 450 nm blue laser.

Replace the laser with a 900 nm infrared beam.

Replace the laser with a 225 nm ultraviolet beam.

Replace the sodium target with silicon (work function ~ 4.8 eV).

Answer 1

In the photoelectric effect, we have to increase the intensity in order to increase the current. So, in order to double the current we have to double the intensity of 450 nm blue laser