Electromagnetic Spectrum Overview

Electromagnetic Spectrum

• Electromagnetic waves travel at 3.0 × 10⁸ m/s in a vacuum.
• The spectrum's order (high to low frequency): Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.
• Wavelength order is the reverse.
• Radio waves: Used for radio/TV transmissions, astronomy, and RFID.
• Microwaves: Used for satellite communication, mobile phones, and microwave ovens. Internal heating of body cells is a potential harmful effect.
• Infrared: Used in remote controls, thermal imaging, and optical fibers. Skin burns are a potential harmful effect.
• Visible light: Used for vision, photography, and illumination.
• Ultraviolet: Used for security marking, detecting counterfeits, and sterilizing water. Can cause skin cancer and eye damage.
• X-rays: Used for medical imaging and security scanning. Cell mutations and tissue damage are potential harmful effects.
• Gamma rays: Used for sterilizing medical equipment and cancer treatment. Cell mutations and tissue damage are potential harmful effects.

Satellite Communication

• Low-orbit satellites use microwaves.
• Geostationary satellites use direct broadcast for TV and internet.

Communication Systems

• Mobile phones use microwaves for wall penetration, requiring a shorter antenna.
• Bluetooth uses radio waves, which are weaker through walls.
• Optical fibers use visible light or infrared for high-speed data transmission.

Digital vs. Analog Signals

• Digital signals offer better accuracy, easier regeneration, and longer transmission ranges compared to analog.
• Sound can be transmitted as either digital or analog.

Sound

• Sound is a longitudinal wave produced by vibrating sources.
• Human hearing ranges from 20 Hz to 20,000 Hz.
• Sound requires a medium (air, water, etc.) to travel.
• The speed of sound in air is approximately 330-350 m/s.
• Sound speed is calculated using the time taken and distance traveled.
• Sound amplitude relates to loudness; frequency relates to pitch.
• An echo is a reflected sound wave.
• Ultrasound has a frequency greater than 20 kHz.

Sound Wave Properties

• Compression and rarefaction are fundamental to longitudinal sound waves.
• Sound travels fastest in solids, slower in liquids, and slowest in gases.

Ultrasound Applications

• Ultrasound is utilized in non-destructive testing.
• Medical imaging uses ultrasound for soft tissue scanning.
• Sonar, using ultrasound, measures depth and distance.

This quiz covers the fundamental aspects of the electromagnetic spectrum, including the types of electromagnetic waves, their respective uses, and potential harmful effects. Test your understanding of how these waves travel and their implications in various fields such as communication and medicine.