Waves

1
Waves
2
Types of waves

• Transverse displacement wave
• examples water, light
• Longitudinal compression wave
• examples sound, earthquake (p wave)

3
Parts of a Wave
crest
Amplitude (a)
Node
trough
Wavelength (?)
Frequency (f) waves/second
V f? Velocity frequency x wavelength
4
Properties of Waves
5
Reflection

• Waves bouncing back from a barrier.
• Angle of incidence equals the angle of reflection
  when measured from the normal (perpendicular
  line).

6
Refraction

• Bending of waves as the go from one medium
  (substance) to another.
• Snells Law n1sinT1 n2sinT2
• N index of refraction, a value that differs
  with the substance

7
Diffraction

• Bending of waves as they pass around a barrier.
• Maximum diffraction comes with small slits and
  long wavelengths.

8
Interference

• Two or more waves interacting.
• Constructive interference crest meets crest or
  trough meets trough.
• Destructive Interference crest meets trough.

9
1st order maximum
Central Maximum
1st order minimum
Tan T x/L
D sin T n ?
10
Resonance

• An object vibrating at its own natural
  frequency.
• For a closed tube, ? 4(l 0.4d) and v f ?
• v 332 m/s (0.6 m/s)(T)

11
Polarization

• Polarized filters are filters with many lines
  oriented in the same direction with a width
  smaller than the amplitude of light.
• Light waves oriented perpendicular to the
  openings in the filter cannot get through, while
  those oriented in the same direction can.
• Reflected light from cars, water, roads, etc, is
  reflected horizontally, so polarized sunglasses
  are polarized vertically.

12
Electromagnetic Spectrum

• Made of waves traveling at the speed of light
  (3 x 108 m/s)
• In order, lowest energy to highest power,
  radio, microwave, infrared, visible, ultraviolet,
  x-ray, gamma, and hard-gamma.
• Energy is directly related to frequency.