How do I calculate energy from wavelength?
To calculate photon energy from wavelength, use Planck's equation: E = hc/λ, where h is Planck's constant (6.626 × 10⁻³⁴ J⋅s), c is the speed of light (3 × 10⁸ m/s), and λ is the wavelength in meters. See also our Pressure Conversion Calculator.
How do I find the energy in joules given the wavelength?
Convert the wavelength to meters, then apply E = hc/λ. For example, for 550 nm light: convert to 550 × 10⁻⁹ m, then calculate E = (6.626 × 10⁻³⁴ × 3 × 10⁸) / (550 × 10⁻⁹) = 3.61 × 10⁻¹⁹ J.
How do I convert wavelength to energy in eV?
First calculate energy in joules using E = hc/λ, then convert to electronvolts by dividing by the elementary charge (1.602 × 10⁻¹⁹ C). Alternatively, use the direct formula: E(eV) = 1240/λ(nm).
What is the relationship between frequency and wavelength?
Frequency and wavelength are inversely related by the speed of light: c = λf, where c is the speed of light, λ is wavelength, and f is frequency. Higher frequency means shorter wavelength.
What is the energy of a 100 nm photon?
A 100 nm photon has an energy of approximately 12.4 eV or 1.99 × 10⁻¹⁸ joules. This is in the ultraviolet range of the electromagnetic spectrum.
What are typical wavelength ranges for different types of electromagnetic radiation?
Visible light: 380-700 nm, UV: 10-380 nm, infrared: 700 nm-1 mm, radio waves: 1 mm-100 km, X-rays: 0.01-10 nm, gamma rays: <0.01 nm.
Why is Planck's constant important in these calculations?
Planck's constant (h = 6.626 × 10⁻³⁴ J⋅s) is fundamental to quantum mechanics and relates the energy of a photon to its frequency or wavelength. It's the proportionality constant in Planck's equation E = hf.