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Maximum Kinetic Energy Formula:
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The Maximum Kinetic Energy formula \( KE_{max} = h f - \phi \) is a fundamental equation in quantum physics that describes the maximum kinetic energy of electrons emitted during the photoelectric effect, where h f is the photon energy and φ is the work function of the material.
The calculator uses the photoelectric equation:
Where:
Explanation: This equation demonstrates that the maximum kinetic energy of photoelectrons equals the photon energy minus the minimum energy required to eject an electron from the material surface.
Details: Calculating maximum kinetic energy is essential for understanding quantum phenomena, designing photoelectric devices, and verifying the particle nature of light in physics experiments.
Tips: Enter photon energy and work function values in electronvolts (eV). Both values must be non-negative, and photon energy should be greater than work function for electron emission to occur.
Q1: What happens if photon energy is less than work function?
A: If h f < φ, no photoelectrons are emitted regardless of light intensity, demonstrating the threshold frequency concept.
Q2: What are typical work function values?
A: Work functions typically range from 2-6 eV for most metals. For example, cesium has ~2.1 eV while platinum has ~5.6 eV.
Q3: Why is maximum kinetic energy important?
A: KE_max determines the stopping potential in photoelectric experiments and helps verify Einstein's photoelectric equation.
Q4: Does light intensity affect maximum kinetic energy?
A: No, light intensity affects the number of photoelectrons but not their maximum kinetic energy, which depends only on photon frequency.
Q5: What units should be used for this calculation?
A: Electronvolts (eV) are most convenient, but consistent energy units (joules can be used with appropriate conversion factors).