Saturation Current
The maximum photocurrent obtained when all emitted photoelectrons reach the collector plate, indicating the rate of electron emission.
What is Saturation Current?
The maximum constant photocurrent obtained in the photoelectric effect when the collector plate is at a sufficiently positive potential to collect all the photoelectrons emitted from the emitter.
Key formula / rule: Saturation Current and Intensity
Key points
- Define saturation current.
- Explain the conditions under which saturation current is observed.
- Relate saturation current to the intensity of incident radiation.
- Differentiate saturation current from other parameters of the photoelectric effect.
Common exam trap
Confusing saturation current with stopping potential.
Definitions
- Term
Saturation Current
- Meaning
The maximum constant photocurrent obtained in the photoelectric effect when the collector plate is at a sufficiently positive potential to collect all the photoelectrons emitted from the emitter.
- Term
Photocurrent
- Meaning
The electric current produced due to the emission of electrons from a material when light falls on it.
Learning objectives
Define saturation current.
Explain the conditions under which saturation current is observed.
Relate saturation current to the intensity of incident radiation.
Differentiate saturation current from other parameters of the photoelectric effect.
Formulae
- Name
Saturation Current and Intensity
- Note
This proportionality holds true as long as the frequency of incident light is above the threshold frequency.
- Expression
Isat \propto \text{Intensity of incident light}
- Name
Saturation Current and Electron Emission Rate
- Note
Where 'n' is the number of photoelectrons emitted per second, and 'e' is the elementary charge.
- Expression
Isat = n \× e
Prerequisites
Photoelectric effect
Work function
Threshold frequency
Kinetic energy of photoelectrons
Intensity of light
Common mistakes
Confusing saturation current with stopping potential.
Assuming saturation current depends on frequency rather than intensity.
Not understanding that saturation current is limited by the rate of electron emission, not the collector potential itself.
Keywords
Photoelectric effect
Saturation current
Photocurrent
Intensity of light
Electron emission
Collector plate
NEET Physics
Practice preview
In a photoelectric effect experiment, if the intensity of incident light is increased, what happens to the saturation current?…
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When monochromatic light of intensity I and frequency ν is incident on a metal surface, photoelectrons are emitted. If the intensity of the light is doubled to 2I, while the frequency remains ν, how does the saturation c…
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In a photoelectric experiment, the saturation current is found to be I. If the frequency of the incident light is kept constant but the intensity is increased such that the number of photons incident per unit area per un…
medium