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Maximum Kinetic Energy Equation:
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The maximum kinetic energy equation (KE_max = hf - φ) describes the maximum energy that photoelectrons can have when emitted from a material due to the photoelectric effect. This fundamental equation in quantum mechanics demonstrates the particle nature of light.
The calculator uses the photoelectric equation:
Where:
Explanation: The equation shows that the maximum kinetic energy of emitted electrons equals the energy of the incident photon (hf) minus the work function (the minimum energy needed to eject an electron from the material).
Details: Calculating maximum kinetic energy is essential for understanding the photoelectric effect, designing photoelectric devices, and studying quantum phenomena in materials science and electronics.
Tips: Enter Planck's constant in eV·s (default is 4.14e-15), frequency in Hz, and work function in eV. All values must be non-negative.
Q1: What is the photoelectric effect?
A: The photoelectric effect is the emission of electrons when light strikes a material. Einstein's explanation of this phenomenon earned him the Nobel Prize and helped establish quantum theory.
Q2: What is the work function?
A: The work function is the minimum energy needed to remove an electron from the surface of a material. It varies between different materials.
Q3: Why does kinetic energy depend on frequency but not intensity?
A: According to quantum theory, each photon's energy depends on its frequency (E = hf). Intensity affects the number of electrons emitted, not their maximum energy.
Q4: What happens if hf is less than φ?
A: If the photon energy is less than the work function, no electrons are emitted regardless of light intensity. This demonstrates the threshold frequency concept.
Q5: What are practical applications of this equation?
A: This principle is used in photomultiplier tubes, solar cells, image sensors, and various light detection systems.