# Photoelectric Effect, Work Function, Threshold Frequency, Wavelength, Speed & Kinetic Energy, Electr | Summary and Q&A

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September 24, 2017
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The Organic Chemistry Tutor
Photoelectric Effect, Work Function, Threshold Frequency, Wavelength, Speed & Kinetic Energy, Electr

## TL;DR

The photoelectric effect involves the ejection of electrons from a metal surface when light of a certain frequency is shone on it.

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### Q: What is the photoelectric effect?

The photoelectric effect refers to the ejection of electrons from a metal surface when light of a specific frequency shines on it. The electrons gain enough kinetic energy from the photons to overcome the metal's atomic forces and escape.

### Q: How does the frequency of light affect the photoelectric effect?

The frequency of light determines whether electrons can be ejected from a metal surface. Low-frequency light, such as red light, typically lacks the required energy to eject electrons. High-frequency light, like blue light, has enough energy to remove electrons from the metal.

### Q: What is the significance of the threshold frequency?

The threshold frequency is the minimum frequency of light required to eject electrons from a metal surface. If the light's frequency is below the threshold, no electrons will be ejected, regardless of the light's intensity. Increasing the intensity only affects the number of ejected electrons above the threshold frequency.

### Q: How can we calculate the threshold frequency?

The threshold frequency can be calculated using the equation: work function (or e_naught) = Planck's constant × threshold frequency. By rearranging the equation, the threshold frequency can be determined by dividing the work function by Planck's constant.

## Summary & Key Takeaways

• The photoelectric effect occurs when light of the right frequency shines on a metal, causing electrons to be ejected off its surface.

• Light wavelength determines whether electrons can be ejected, with high-frequency light being more effective than low-frequency light.

• The threshold frequency is the minimum frequency required to eject electrons, with increasing intensity only affecting the number of ejected electrons.