Photoelectric Effect: Current & Voltage Effects

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Homework Statement

1. If frequency is constant and intencity of light is doubled what happen to the current?
2. If frequency is constant and intencity of light is doubled what happen to the voltage?
3. If intencity is constnat and frequency of light is doubled what happen to the current?
4. If intencity is constnat and frequency of light is doubled what happen to the voltage?

Homework Equations

E = hf

The Attempt at a Solution

I know the intencity of light is proportional to the number of photons
and frequency of light is is proportional to the energy of photons
So my answer is

1. current doubled
2. no change
3. no change
4. voltage doubled

am I right?

 

[Chewy0087]

yes, you are, though would the voltage be exactly doubled with the frequency bieng doubled? Think about the work function and try it mathematically.

 

[nlightner]

Your answer is partially correct. The photoelectric effect is a phenomenon where electrons are ejected from a metal surface when it is exposed to light. The intensity of light refers to the amount of light hitting the surface, while the frequency of light refers to the energy of individual photons.

1. If the intensity of light is doubled, the number of photons hitting the surface also doubles, causing more electrons to be ejected and thus increasing the current.
2. The voltage is the measure of the potential energy of the electrons. Doubling the intensity of light does not change the energy of individual photons, so there is no change in voltage.
3. If the frequency of light is doubled, each photon has more energy and can eject more electrons. This results in an increase in current.
4. The voltage is still a measure of the potential energy of the electrons, so doubling the frequency of light does not change the voltage.