Gamma rays are not deflected by electric or magnetic fields.
Why Gamma Rays Aren't Deflected
Unlike alpha and beta particles, gamma rays are electromagnetic radiation, not charged particles. They are high-energy photons, meaning they have no mass and no electric charge. The deflection of charged particles by electric and magnetic fields relies on the interaction between the moving charge and the field. Since gamma rays have no charge, they do not interact with these fields in a way that causes them to change direction.
Comparison with Alpha and Beta Particles
To understand why gamma rays aren't deflected, it's helpful to compare them to alpha and beta particles:
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Alpha Particles: These are helium nuclei (2 protons and 2 neutrons) and carry a positive charge. Therefore, they are deflected by electric and magnetic fields. Due to their relatively large mass, their deflection is less pronounced compared to beta particles.
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Beta Particles: These are high-energy electrons or positrons and carry a negative (or positive for positrons) charge. They are also deflected by electric and magnetic fields. Because they are much lighter than alpha particles, they experience a greater deflection.
The following table summarizes these differences:
| Particle | Composition | Charge | Mass | Deflection by Electric/Magnetic Field |
|---|---|---|---|---|
| Alpha | Helium Nucleus | +2e | High | Yes, but less than Beta |
| Beta | Electron/Positron | -e/+e | Low | Yes, significant |
| Gamma | Photon | 0 | 0 | No |
Applications
The fact that gamma rays are not deflected is useful in various applications, such as:
- Sterilization: Gamma rays are used to sterilize medical equipment and food because they can penetrate materials effectively without being easily diverted.
- Cancer Treatment (Radiotherapy): Focused beams of gamma rays are used to kill cancer cells. Their straight-line path allows precise targeting.
- Industrial Radiography: Gamma rays can be used to inspect welds and other materials for defects. Their ability to pass through materials without deflection provides clear images.
- Astronomy: Astronomers study gamma rays from space to learn about the most energetic phenomena in the universe. Since they travel in straight lines, they provide precise information about their sources.
