Electromagnetic Waves and Light

Flashcards covering the properties, spectrum, interactions, and applications of electromagnetic waves and light.

Electromagnetic (EM) waves

Created when charged particles accelerate, causing oscillating electric and magnetic fields that travel through space.

Speed of Light

Approximately 3.00×10^8 m/s in a vacuum; the speed at which EM waves travel.

Formulas for EM waves

c=fλ (speed of light = frequency x wavelength) and E=hf (energy = Planck’s constant x frequency).

Wavelength and Frequency Relationship

Inversely related; as one increases, the other decreases.

Energy and Frequency Relationship

Directly proportional; high-frequency waves carry more energy.

Electromagnetic Spectrum

Arrangement of all EM waves by frequency and wavelength, ranging from radio waves to gamma rays.

Major Regions of EM Spectrum

Radio, microwave, infrared, visible light, ultraviolet, X-rays, and gamma rays (in order of increasing frequency and energy).

Uses of Radio Waves

Communication

Uses of Microwaves

Cooking and satellite communication.

Uses of Infrared Waves

Thermal imaging

Uses of Visible Light

Vision

Uses of Ultraviolet Waves

Sterilization

Uses of X-Rays

Medical imaging.

Uses of Gamma Rays

Cancer treatment.

Five Main Ways Light Interacts with Matter

Emission, transmission, reflection, absorption, and scattering.

Reflection

Light bouncing off surfaces, following the law that the angle of incidence equals the angle of reflection.

Scattering

Light redirected in many directions, affecting shorter wavelengths (blue light) more strongly.

Visible Light Spectrum Range

About 400 nm (violet) to 700 nm (red).

Cones

Photoreceptor cells in human eyes responsible for color vision; sensitive to red, green, and blue wavelengths.

Rods

Photoreceptor cells in human eyes that detect light in low-light conditions but do not detect color.

Additive Color Mixing

Creating colors using red, green, and blue light, as done by screens.

Rayleigh Scattering

The reason the sky is blue; molecules in the atmosphere scatter shorter wavelengths (blue) more than longer ones (red).