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Photon Energy Formula:
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The photon energy formula \( E = \frac{hc}{\lambda} \) calculates the energy of a photon based on its wavelength, where E is energy in joules, h is Planck's constant, c is the speed of light, and λ is the wavelength in meters.
The calculator uses the photon energy equation:
Where:
Explanation: The equation shows that photon energy is inversely proportional to its wavelength - shorter wavelengths correspond to higher energy photons.
Details: Calculating photon energy is essential in quantum mechanics, spectroscopy, photochemistry, and understanding electromagnetic radiation across the spectrum from radio waves to gamma rays.
Tips: Enter wavelength in meters, Planck's constant in J·s, and speed of light in m/s. Default values are provided for Planck's constant (6.626 × 10⁻³⁴) and speed of light (3 × 10⁸).
Q1: What are typical wavelength values for visible light?
A: Visible light wavelengths range from approximately 380 nm (violet) to 750 nm (red), which is 3.8 × 10⁻⁷ m to 7.5 × 10⁻⁷ m.
Q2: Can I calculate energy in electronvolts instead of joules?
A: Yes, divide the result in joules by 1.602 × 10⁻¹⁹ to convert to electronvolts (eV), which is commonly used in atomic physics.
Q3: How does photon energy relate to frequency?
A: The formula can also be written as E = hf, where f is frequency. This is equivalent since c = λf.
Q4: What is the energy of a photon with wavelength 500 nm?
A: Approximately 3.97 × 10⁻¹⁹ J or 2.48 eV (using λ = 5 × 10⁻⁷ m, h = 6.626 × 10⁻³⁴ J·s, c = 3 × 10⁸ m/s).
Q5: Why is Planck's constant so small?
A: Planck's constant is fundamental to quantum mechanics and represents the extremely small quantum of action, reflecting the discrete nature of energy at atomic scales.