Definition and Derivation of Compton Effect Equation

Definition and Derivation of Compton Effect Equation

The Compton effect is a phenomenon that occurs when x-rays or gamma rays are scattered on a material, resulting in an increase in wavelength. This effect was first studied by Arthur Compton in 1922 and is named after him. In this article, we will delve into the definition and derivation of the Compton effect equation.

What is Compton Effect?

The Compton effect is defined as the effect that is observed when x-rays or gamma rays are scattered on a material with an increase in wavelength. The Compton effect is given by the following mathematical form:

$$\lambda_{s} – \lambda_{0} = \frac{h}{m_{0}c}(1-cos\Theta)$$

Where,

  • $\Theta$: the angle at which radiation scattered
  • $m_{0}$: rest mass of an electron
  • $h/m_{0}c$: Compton wavelength of the electron
  • $\lambda_{s}$ and $\lambda_{0}$: radiation spectrum peaks

Derivation

To derive the Compton effect equation, we need to consider the elastic collision between a photon and an electron. The following equations describe the conservation of momentum in the x-direction and y-direction:

$$p_{i} = p_{f}cos\Theta + p_{e}cos\phi (1)$$

$$0 = -p_{f}sin\Theta + p_{e}sin\phi (2)$$

Squaring both sides of equation (1) and using the fact that $p^{2}{e}=p^{2}{i}$, we get:

$$p_{e}^{2} = p_{e}^{2}(cos^{2}\phi + sin^{2}\phi )$$

$$= (p_{i}-p_{f}cos\Theta)^{2}+p_{f}^{2}sin^{2}\Theta$$

$$= p_{i}^{2}+p_{f}^{2}-2p_{i}p_{f}cos\Theta$$

Substituting the expression for $p_{e}$ in terms of $h\nu$ and $m_{0}c$, we get:

$$h\nu + m_{0}c^{2} = h\nu + \sqrt{(m_{0}^{2}c^{4}+p_{e}^{2})}$$

Simplifying this equation, we get the Compton effect equation.

Difference Between Compton Effect and Photoelectric Effect

The Compton effect is caused by the inelastic scattering of high-energy photons that are bound to free electrons. On the other hand, the photoelectric effect is caused by the weakly bound electrons that are ejected from the surface of the material when electromagnetic radiation interacts with the electrons.

Compton Effect Photoelectric Effect
Inelastic scattering of high-energy photons Weakly bound electrons ejected from the surface
Free electrons Low-energy electrons
Higher wavelength scattered photon Wavelength not observed as photon disappears

In this article, we have derived the Compton effect equation and discussed the difference between the Compton effect and photoelectric effect. The Compton effect is a fundamental way in which radiating energy is absorbed by matter. It is an important concept in physics that has many practical applications.

Frequently Asked Questions (FAQs)

Q1: What is an X-ray?

A1: An X-ray is a penetrating type of electromagnetic radiation with a wavelength from 10 picometers to 10 nanometers.

Q2: What is a gamma-ray?

A2: A gamma-ray is another penetrating type of electromagnetic radiation generated from the radioactive decay of atomic nuclei. It has the shortest wavelength among the important electromagnetic waves.

Q3: What is meant by radiation?

A3: Radiation is the transmission or emission of energy in the form of particles or waves through a medium or vacuum.

Q4: What is meant by the photoelectric effect?

A4: The photoelectric effect is a process in which electrons are emitted from a metal's surface when light strikes it.

Q5: Who discovered the Compton effect?

A5: Arthur Compton discovered the Compton effect.

Q6: What is meant by the Compton effect?

A6: The Compton effect is the enlargement of wavelengths of X-rays and other EM waves that have been scattered by electrons. It is a fundamental way in which radiating energy is absorbed by matter.

Q7: What is wavelength?

A7: A wavelength is a length between successive troughs or crests.

Q8: Which symbol is used to represent the Compton wavelength?

A8: The Compton wavelength is represented by the letter λ (Lambda).

Q9: What is a photon?

A9: A photon is a fundamental particle that is the force carrier of electromagnetic force. It is massless and travels at the speed of light.

Q10: Who explained the photoelectric effect?

A10: Albert Einstein explained the photoelectric effect.

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Frequently Asked Questions – FAQs