Ram and Satra are performing photo electric effect in the lab.
The number of electrons coming out from the emitter plate is same for both of them but in Ram's setup the electrons come out with velocity V while in Satra's setup they come out with 2V. Who will record a higher Photo current?
Ram and Satra are performing photo electric effect in the lab.
The number of electrons coming out from the emitter plate is same for both of them but in Ram's setup the electrons come out with velocity V while in Satra's setup they come out with 2V. Who will record a higher Photo current?
The correct option is C Both with have same current
Let's think backwards
The current is measured when photo electrons hit the collector plate.
The number of photo electrons that hit the collector plate is equal to the number of photo electrons ejected out by the emitter.
The rate at which electrons are emitted out by emitter is fixed and same for both. This depends upon the intensity.
Thought experiment:
10 photons per sec fall on the emitter. Assume 100% efficiency
The emitter emits 10 electrons per second and the field is so high in the tube that all the emitted electrons are received in half a sec only. Still the collector will just have to sit idle for the next half of the second as there are going to be no electrons. Only the next second the electrons will start to come in.
So technically if I ask the collector that how many electrons did you receive per second his answer is still going to be 10 even though he received all 10 in half second and was idle for the next half.
Therefore the current measured by the collector or the rate of charge collected depends upon the rate at which they are emitted and not the speed at which they flow in the tube.
Since in both Ram's and Satra's experiment the number of electrons ejected are same so will the current.
Similarly in the photoelectric experiment when you increase the potential across the plates keeping the frequency and intensity constant the photo current doesn't increase , it saturates.
Both with have same current
Let's think backwards
The current is measured when photo electrons hit the collector plate.
The number of photo electrons that hit the collector plate is equal to the number of photo electrons ejected out by the emitter.
The rate at which electrons are emitted out by emitter is fixed and same for both. This depends upon the intensity.
Thought experiment:
10 photons per sec fall on the emitter. Assume 100% efficiency
The emitter emits 10 electrons per second and the field is so high in the tube that all the emitted electrons are received in half a sec only. Still the collector will just have to sit idle for the next half of the second as there are going to be no electrons. Only the next second the electrons will start to come in.
So technically if I ask the collector that how many electrons did you receive per second his answer is still going to be 10 even though he received all 10 in half second and was idle for the next half.
Therefore the current measured by the collector or the rate of charge collected depends upon the rate at which they are emitted and not the speed at which they flow in the tube.
Since in both Ram's and Satra's experiment the number of electrons ejected are same so will the current.
Similarly in the photoelectric experiment when you increase the potential across the plates keeping the frequency and intensity constant the photo current doesn't increase , it saturates.
