1. What is Photon Momentum?

Photon momentum is a fundamental concept in quantum mechanics that describes the momentum carried by photons, the elementary particles of light. Despite having no mass, photons possess momentum due to their wave-particle duality.

2. How Does the Calculator Work?

The calculator uses the photon momentum formula:

Where:

• \( p \) — Photon momentum (kg·m/s)
• \( h \) — Planck's constant (6.62607015 × 10⁻³⁴ J·s)
• \( \lambda \) — Wavelength of the photon (m)

Explanation: The momentum of a photon is inversely proportional to its wavelength. Shorter wavelengths correspond to higher energy photons with greater momentum.

3. Importance of Photon Momentum Calculation

Details: Calculating photon momentum is essential in understanding phenomena like radiation pressure, Compton scattering, and the operation of solar sails. It demonstrates how light can exert force on matter despite having no mass.

4. Using the Calculator

Tips: Enter Planck's constant in J·s (default value is provided) and wavelength in meters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How can photons have momentum without mass?
A: In special relativity, momentum is not solely dependent on mass. Photons have momentum due to their energy and wave properties, described by p = E/c where E is energy and c is light speed.

Q2: What is a typical photon momentum value?
A: Photon momentum is extremely small. For visible light (λ ≈ 500 nm), p ≈ 1.3 × 10⁻²⁷ kg·m/s, which is why we don't feel pressure from ordinary light.

Q3: How is photon momentum related to light pressure?
A: Light pressure results from photons transferring their momentum to surfaces they strike. This principle enables technologies like solar sails for spacecraft propulsion.

Q4: Can photon momentum be observed in everyday life?
A: While too small to notice in daily experience, photon momentum is measurable in precise laboratory experiments and is crucial in atomic physics experiments.

Q5: How does photon momentum relate to the Compton effect?
A: The Compton effect demonstrates photon momentum directly, showing how X-ray photons transfer momentum to electrons, resulting in wavelength changes that depend on scattering angle.