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.