Physics BASIS 8 : Trends in EM, Reflection, & Refraction

Speed of Light: c = 3.0 × 10⁸m/s

As wavelength goes up, frequency goes down, and vice-versa

Electromagnetic Spectrum: range of electromagnetic waves when placed in order of increasing frequency & energy

Radio Waves: largest wavelengths
Microwaves: shorter than radio, but larger than infrared
Infrared Waves: shortest wavelengths before visible light
Visible Light
- smallest frequency & largest wavelength: red light
- largest frequency & shortest wavelength: violet light
Ultraviolet: encourages our bodies to produce essential vitamins
X-Rays: used for imaging bones & teeth
Gamma Rays: used in PET scans

Opaque: materials that do not allow light to pass through

Transparent: allows light to pass through in straight lines

Refraction: change in direction of a wave as it crosses the boundary between 2 media

Index of Refraction: how much a substance changes the speed of light therefore bends light (A Ratio)
- n = c/v : n = index, c = speed of light, v = speed of light in medium
- higher density = lower speed = higher n
Incident Ray: ray that heads toward boundary
Refracted Ray: ray that heads away from boundary
Normal Line: imaginary line drawn perpendicular to boundary where the ray hits
- Angle of Incidence: angle between incident ray & norm. line
- Angle of Refraction: angle between refracted ray & norm. line
  - When a wave slows down, it bends toward the normal
  - When a wave speeds up, it bends away from the normal
Snell’s Law: n₁sin(θ_i) = n₂sin(θ_r)

Reflection: when a light ray strikes off a smooth surface and bounces off

Law of Reflection: θ_i = θ_r