COMPTON EFFECT

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COMPTON EFFECT

Compton Effect

The Compton Effect is the increase in the wavelength of an X-ray or gamma-ray photon when it collides with a free or loosely bound electron. During the collision, the photon transfers part of its energy and momentum to the electron, causing the electron to recoil and the scattered photon to emerge with lower energy and a longer wavelength. This phenomenon was discovered by Arthur H. Compton in 1923 and provided strong evidence for the particle nature of light. The Compton Effect cannot be explained by classical wave theory and is considered one of the key experimental foundations of quantum mechanics.

Main Formula of Compton Effect

The Compton shift in wavelength is given by the equation:

Δλ = λ′ − λ = h/mₑc (1 − cos θ)

where λ is the incident wavelength, λ′ is the scattered wavelength, h is Planck’s constant, mₑ is the mass of an electron, c is the speed of light, and θ is the scattering angle. This formula shows that the change in wavelength depends only on the scattering angle and not on the initial wavelength or intensity of light. The maximum wavelength shift occurs when the scattering angle is 180°, while no shift occurs when the angle is 0°.

Meaning of Symbols in Compton Effect

Several physical quantities are used in the Compton Effect equation. The symbol λ represents the wavelength of the incident photon before collision, while λ′ represents the wavelength after scattering. The difference between them, Δλ, is known as the Compton shift. Planck’s constant (h) is a fundamental constant that relates energy and frequency of photons. The electron mass is represented by mₑ, and c denotes the speed of light in a vacuum. The symbol θ is the angle through which the photon is scattered. Together, these quantities help describe the interaction between photons and electrons quantitatively.

Key Points of Compton Effect