Correct graph of current vs voltage (photoelectric emission)

[songoku]

Homework Statement

The diagram shows a circuit used for the investigation of photoelectric emission. The two electrodes E and F are made of different metals. The work function of electrode E is higher than that of electrode F.

Which of the following graphs show the variation the current (flows from E to F) versus voltage (of E with respect to F) when the two electrodes are illuminated with a uniform monochromatic light? Assume the magnitude of the saturation current for either electrodes is same during this experiment

Homework Equations

Not sure

The Attempt at a Solution

1. E has higher work function means that the electrons are harder to be released from E but I do not know how work functions affects the question

2. When current = 0, is the voltage = stopping potential?

3. My guess:
The graph starts from negative voltage, means that the voltage of E is lower than F. Photoelectrons will be attracted to F so the electrons will flow from F to E and current from E to F resulting in positive value of current. When the voltage changes (becomes more positive) the current will decrease until zero then flow in opposite direction resulting in negative value of current. The answer is C ?

Thanks

 

[haruspex]

My guess:
The graph starts from negative voltage, means that the voltage of E is lower than F. Photoelectrons will be attracted to F so the electrons will flow from F to E and current from E to F resulting in positive value of current. When the voltage changes (becomes more positive) the current will decrease until zero then flow in opposite direction resulting in negative value of current. The answer is C ?

Your argument is reasonable, but only leads to A or C.
To distinguish those, consider zero applied voltage. What will shining a light on the electrodes do to each? How might that relate to the work function?

 

[songoku]

Your argument is reasonable, but only leads to A or C.

I think the value of stopping potential will be negative.

To distinguish those, consider zero applied voltage. What will shining a light on the electrodes do to each? How might that relate to the work function?

At that situation, electron will be easier to be released from F then it will travel to E resulting negative current? So the answer is still C?

Thanks

 

[haruspex]

I think the value of stopping potential will be negative.At that situation, electron will be easier to be released from F then it will travel to E resulting negative current? So the answer is still C?

Thanks

That seems right to me.

 

[songoku]

Thank you very much haruspex