Electromagnetic-Spectrum.my-ppt.-.-week-1

  • Definition: Study of everyday phenomena, matter, energy, and laws of nature.

What is Light?Overview of Physics

  • Light: Electromagnetic radiation in a specific portion of the electromagnetic spectrum.

19th Century Physics

Key Figure

  • James Clerk Maxwell (1831-1879): Made significant contributions to electromagnetic wave theory.

Electromagnetic Wave Theory

  • Light as a transverse wave composed of oscillating electric and magnetic fields at right angles to each other.

  • Radiates energy in the form of electromagnetic (EM) waves.

  • Vibrating electric charges create changing electromagnetic fields capable of wave propagation.

Properties of Electromagnetic Waves

  • Speed of EM Waves: 3 x 10^8 m/s.

  • Photons: Bundles of wave energy; types of EM waves defined by energy carried by photons.

  • Wave Characteristics:

    • Crest: Highest point.

    • Trough: Lowest point.

    • Amplitude: Maximum displacement.

    • Wavelength: Distance between crests.

    • Frequency: Number of waves per second (measured in Hertz).

Electromagnetic Spectrum

  • Range of different wavelengths including:

    • Radio waves (longest wavelength, lowest frequency).

    • Microwaves.

    • Infrared.

    • Visible light (ROYGBIV).

    • Ultraviolet.

    • X-rays.

    • Gamma rays (shortest wavelength, highest frequency).

Types of Electromagnetic Waves

Radio Waves

  • Longest wavelength; produced by vibrating electrons in an antenna.

Microwaves

  • Higher frequency and energy than radio waves.

Infrared

  • Not visible but felt as heat; relates to temperature.

Visible Light

  • Separated into colors by prisms; includes red (longest wavelength) and violet (shortest wavelength).

Ultraviolet Rays

  • Emitted by the sun; shorter wavelengths than visible light.

    • Types: UVC, UVB, UVA (increasing wavelength).

X-rays

  • Discovered by Wilhelm Roentgen; useful for medical tests.

Gamma Rays

  • Emitted by stars; very dangerous, blocked only by lead/concrete.

Summary Notes

  • As energy increases, frequency increases and wavelength decreases.

  • Electromagnetic radiation can be both useful and hazardous.