#3_Compton_Effect_Alegado,Marvin_Castillo.pptx

The Compton effect, also known as Compton scattering, occurs when high-frequency photons collide with electrons in matter. During this interaction, the photons transfer energy and momentum to the electrons, resulting in scattered photons with longer wavelengths. This phenomenon provides insights into both the wave and particle properties of radiation, bridging classical and quantum physics.

1. PHYED 151 Topic 3 REPORTER: ALEGADO, MARVIN C.

2. Learning Objectives After the report, the students should be able to: explain how X-rays are scattered by electrons and how this leads to a change in wavelength; compare classical wave theory with the observed results of the Compton Effect; calculate the wavelength shift using the Compton formula; and explore practical applications of the Compton Effect, such as X-ray imaging and diffraction.

3. Elicit: Warm-Up Activity

4. Elicit: Review

5. Introduction We will further discuss the Compton effect, which played a very important role in providing irrefutable evidence for the picture of light, where light behaves like packets or particles or photons.

6. Engage 1. What do you think are the similarities of the billiard games to the Compton effect? 2. How do they relate to each other?

7. Activity 1: The Compton Effect Experiment Explore

8. Guide Questions: What is the Compton Effect? What changes do you observe in the scattered radiation compared to the incident radiation? What is the relationship between the scattering angle and the wavelength shift? How does the Compton Effect challenge classical wave theory? What implications does the Compton Effect have for our understanding of light?

9. https://youtu.be/zTzJJ9lGP0U?si=RtyeHrNk6FjAxB9L Compton Effect Experiment Explore

10. Explain Compton Effect Overview: When a high-energy photon (e.g., an X-ray) collides with an electron, it transfers some of its energy and momentum to the electron. As a result, the photon changes direction (scatters) and experiences a wavelength shift (increase in wavelength).

11. Explain B. Changes in Scattered Radiation: Compared to the incident radiation (original X-ray), the scattered radiation has: Increased wavelength : The wavelength of the scattered photon becomes longer. Decreased energy : The scattered photon loses energy during the interaction. The Compton shift ( Δλ ) quantifies this change in wavelength.

12. Explain C. Scattering Angle and Wavelength Shift: The scattering angle (θ) between the incident and scattered directions determines the amount of wavelength shift. The greater the scattering angle, the larger the wavelength shift. If ϑ is small, ∆λ is small. If ϑ is large, ∆λ is large. The relationship is described by Compton’s equation: Δλ = h / ( m e c ) * (1 - cos θ), where h is Planck’s constant, m e is the electron mass, and c is the speed of light.

13. Explain D. Challenge to Classical Wave Theory: Classical wave theory predicts that the wavelength of scattered radiation should remain unchanged. However, the Compton Effect demonstrates that light behaves as both waves and particles ( photons ). This challenged classical physics and led to the development of quantum mechanics.

14. Explain CLASSICAL WAVE THEORY Observed Results of the Compton Effect When an electromagnetic wave (such as X-rays) interacts with charged particles (such as electrons), the scattered radiation should have the same frequency and wavelength as the incident radiation. In Thomson scattering, the electromagnetic field of the incoming wave accelerates an electron via the Lorentz force but does no work upon it. The electron oscillates at the same frequency as the incoming wave and then re-emits (scatters) light at that same frequency as a classical oscillating electric dipole. This process is elastic, meaning no net energy is given to the electron. The Compton Effect, observed experimentally, contradicts classical predictions. When X-rays scatter off electrons, the scattered light has a lower frequency and longer wavelength than the incident X-rays. The frequency shift depends on the scattering angle. Importantly, this behavior is not dependent on the intensity (electric field amplitude) of the incident radiation. The Compton Effect demonstrates that light cannot be explained purely as a wave phenomenon. Instead, it supports the photon model, where light behaves as particles (photons) with momentum and energy.

15. Explain E. Implications for Our Understanding of Light: The Compton Effect solidifies the concept of wave-particle duality. It shows that light cannot be purely explained as continuous waves; it also exhibits particle-like behavior.

16. Elaborate Derivation of the Compton Shift Equation

17. Elaborate Photons with a wavelength of 0.05 nm are scattered from a sheet of carbon. What will be the wavelengths of the photons that are scattered at: 45 90 180

18. Practical Applications 1. X-ray Imaging: X-ray imaging relies on the Compton Effect to create detailed images of internal structures in the human body. When X-rays pass through tissues, they scatter due to interactions with electrons. The scattered X-rays provide information about the density and composition of the tissues. Medical X-ray machines use this phenomenon to visualize bones, organs, and soft tissues, aiding in diagnosis and treatment planning.

19. Practical Applications 2. X-ray Diffraction : X-ray diffraction is a powerful technique used to study the atomic and molecular structure of crystalline materials. When X-rays strike a crystal lattice, they scatter in specific directions due to the arrangement of atoms within the crystal. By analyzing the diffraction pattern, scientists can determine the spacing between atoms and the crystal’s symmetry. X-ray diffraction is widely used in materials science, chemistry, and biology to study crystals, proteins, and other complex structures.

20. Practical Applications 3. Security Scanning : Compton scattering is employed in airport security scanners and baggage inspection systems. These scanners use low-energy X-rays to detect hidden objects or suspicious materials. The scattered X-rays provide information about the density and composition of the scanned items.

21. Practical Applications 4. Particle Physics Research : In high-energy physics experiments, Compton scattering plays a role in understanding fundamental particles. Scientists study the scattering of electrons and photons to probe the structure of atomic nuclei and explore the properties of subatomic particles.

22. Wrap-Up Calculate the Compton wavelength of a proton. Reflect on what you’ve learned and what you found interesting or challenging about the lesson.

23. Extend (Homework) Review and prepare for a short quiz next meeting. Conduct further research on the Compton Effect and its applications in various fields such as medicine, archaeology, and engineering. Write a short reflection on what you’ve learned and how you think the Compton Effect can be used in our daily lives.

24. ARIGATHANKS iti MANY!