Dangers and Uses of Electromagnetic Waves

Introduction

• Discusses the dangers and uses of electromagnetic waves.
• Importance of understanding electromagnetic waves and their applications.

Radio Waves

• Main Use: Communication.
  • Long Wave Radio: Can be transmitted and received globally.
    • Diffraction allows bending around obstacles (hills, buildings, Earth's curvature).
  • Short Wave Radio: Uses ionosphere to reflect back to the Earth.
    • Example: Bluetooth devices (e.g., AirPods).
  • FM Radio/TV: Require direct line of sight with transmitter.

Satellite Communications

• Bridges the gap between radio and microwaves.
• Uses high-frequency radio waves or microwaves to communicate with satellites.
• Applications: Satellite TV, phones, internet, military communications.

Microwaves

• Uses: Cooking and communication.
  • Cooking: Absorbed by water molecules in food, transferring thermal energy.
  • Communication: Can pass through Earth's atmosphere.
• Dangers: Potential heating of body cells due to water content.

Infrared

• Uses:
  • Thermal Imaging: Detect heat loss and used in security cameras.
  • Cooking: Heating elements in appliances like toasters.
  • Communications: Used in optical fibers and TV remotes.
• Dangers: Can cause burns if absorbed by skin.

Visible Light

• Uses: Enables vision and is used in photography.
  • Detected by digital cameras, converted into electrical signals.

Ultraviolet (UV)

• Uses:
  • Security: Utilizes fluorescence for invisible markings (e.g., on banknotes).
  • Disinfection: Kills bacteria in water by damaging cells.
• Dangers:
  • Ionizing radiation can cause skin mutation, leading to cancer.
  • Can damage eye cells, potentially leading to blindness.

X-Rays

• Uses:
  • Medical Imaging: Penetrate soft tissue, absorbed by bones, leaving clear images.
  • Airport Security: Detect hidden objects in luggage.
• Dangers: Ionizing radiation that can cause cancer and radiation sickness.

Gamma Rays

• Uses:
  • Sterilization of medical equipment.
  • Cancer detection and treatment: Gamma rays are emitted to identify tumors.
• Dangers: Ionizing radiation that can cause cancer, radiation poisoning, or death.

Conclusion

• Higher energy and smaller frequency radiation pose greater dangers.
• Encouragement to review notes for better understanding of electromagnetic waves.

• Reminder to like, subscribe, and download notes for more insights.