Ch 15 Phy Electromagnetic spectrum

Infrared Radiation (IR)

Invisible radiation beyond red light, associated with thermal radiation and heat from hot objects.

James Clerk Maxwell's Contribution

Proposed that light consists of oscillations in electric and magnetic fields, leading to the concept of electromagnetic waves.

Electromagnetic Spectrum

The complete range of electromagnetic waves, including radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Frequency

The number of oscillations of a wave per second, determining the color of light in the visible spectrum.

Transverse Waves

A type of wave where the oscillation is perpendicular to the direction of the wave's travel, characteristic of all electromagnetic waves.

Speed of Light

The speed at which electromagnetic waves travel in a vacuum, approximately 3 × 10⁸ m/s.

Wavelength

The distance between consecutive peaks of a wave; longer wavelengths correspond to lower frequencies and vice versa.

UV Radiation

Ultraviolet radiation which can cause skin and eye damage, and increase the risk of skin cancer.

Mobile Phones

Devices that utilize microwaves for communication; prolonged use may pose potential risks, especially to children.

Analogue Signals

Continuous signals that can vary in amplitude and frequency, susceptible to distortion and noise.

Digital Signals

Signals that represent data as discrete values (on/off), resulting in clearer, faster, and more accurate transmission.

Geostationary Satellites

Satellites that orbit Earth at about 35,000 km, remaining over a fixed point, used for TV and communication.

Microwaves

Electromagnetic waves with frequencies ranging from radio waves to infrared, used in telecommunications and cooking.

Hazards of Electromagnetic Radiation

EM radiation can be hazardous; IR causes burns, UV causes skin damage, and high-frequency X-rays/gamma rays can lead to cell mutations.

Optical Fibres

Waves that carry light (IR & visible), allowing high-speed data transmission through light pulses.

v = f λ

Formula linking wave speed (v), frequency (f), and wavelength (λ), indicating that higher frequency means shorter wavelength.