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Energy From Wavelength Formula:
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The equation E = (h × c) / λ calculates the energy of a photon from its wavelength, where h is Planck's constant, c is the speed of light, and λ is the wavelength. This fundamental relationship in quantum mechanics connects the wave and particle properties of light.
The calculator uses the energy-wavelength equation:
Where:
Explanation: This equation demonstrates the inverse relationship between photon energy and wavelength - shorter wavelengths correspond to higher energy photons.
Details: Calculating photon energy is essential in various fields including spectroscopy, quantum mechanics, photochemistry, and optical engineering. It helps determine the energy required for electronic transitions and chemical reactions.
Tips: Enter the wavelength in meters. For common wavelengths, remember that 1 nanometer = 10⁻⁹ meters. The wavelength must be greater than zero.
Q1: Why is the energy inversely proportional to wavelength?
A: According to quantum theory, photons with shorter wavelengths have higher frequencies, and since E = hƒ, higher frequency means higher energy.
Q2: What are typical energy values for visible light?
A: Visible light photons (400-700 nm) have energies ranging from approximately 3.1 to 1.8 electronvolts (5.0 × 10⁻¹⁹ to 2.8 × 10⁻¹⁹ joules).
Q3: Can this equation be used for all electromagnetic radiation?
A: Yes, this equation applies to all photons across the electromagnetic spectrum, from radio waves to gamma rays.
Q4: How does this relate to the photoelectric effect?
A: This equation explains why only light above a certain frequency (below a certain wavelength) can eject electrons from a material in the photoelectric effect.
Q5: What are common units for photon energy?
A: While joules are the SI unit, electronvolts (eV) are commonly used in atomic and particle physics (1 eV = 1.602 × 10⁻¹⁹ J).