Waves

• What are the two types of waves?

  Transverse waves and longitudinal waves
• How do transverse waves propagate?

  Vibration is perpendicular to wave direction
• Give an example of a transverse wave.

  Water waves
• What is the equilibrium position in a wave?

  It is the position when the wave vibrates
• What are the highest and lowest points of a wave called?

  Crest and trough
• How do longitudinal waves propagate?

  Vibration is parallel to wave direction
• Give an example of a longitudinal wave.

  Sound waves
• What is a compression in a longitudinal wave?

  Particles are close together and high pressure
• What is a rarefaction in a longitudinal wave?

  Particles are far apart and low pressure
• What does amplitude represent in a wave?

  Energy carried by the wave
• How is wavelength defined?

  Distance between consecutive identical points
• What is the unit of frequency?

  Hertz (Hz)
• What is the period of a wave?

  Time taken for one vibration to pass
• If a wave travels $n$ waves in $t$ seconds, how is frequency calculated?


  Frequency is $n / t$
• How is the speed of a wave calculated?

  Speed is wavelength times frequency
• What are wave fronts?

  Lines along peaks or compressions of waves
• What happens when waves hit an obstacle?

  They are reflected, changing direction
• What is the angle of incidence?

  Angle between incident ray and normal line
• What is the rule of reflection?

  Angle of incidence equals angle of reflection
• What occurs during wave refraction?

  Waves change speed and bend at boundaries
• What happens to wavelength when waves travel from deep to shallow water?

  Wavelength decreases
• What is the Doppler effect?

  Change in frequency due to wave source movement
• What is the speed of light in a vacuum?

  $3 \times 10^8 \text{ m/s}$
• What are the main groupings of the electromagnetic spectrum?

  Radio waves, microwaves, infrared, visible light
• What is the relationship between frequency and energy of electromagnetic waves?

  Higher frequency means higher energy
• What are the uses of radio waves?

  Communication, GPS, and Wi-Fi
• How do microwaves heat food?

  By causing water molecules to vibrate
• What is the effect of ultraviolet light on skin?

  Can cause tanning and skin cancer
• What are the harmful effects of x-rays?

  Can cause internal damage and cancer
• What is the best way to protect from electromagnetic wave harm?

  Limit exposure to radiation sources
• What is the speed of light in air?

  Approximately the same as in vacuum
• What is the angle of incidence when light strikes a mirror?

  Equal to the angle of reflection
• What is the normal line in reflection?

  Line at right angles to the mirror
• What happens to light waves when they reflect off a mirror?

  They change direction but not speed
• What is the significance of the angle of incidence?

  It determines the angle of reflection
• What type of waves are light waves?

  Transverse waves
• How does light travel in a vacuum?

  In straight lines
• What is the relationship between light waves and electromagnetic waves?

  Light waves are a type of electromagnetic wave
• What is the speed of light in a vacuum?

  $3 \times 10^8 \text{ m/s}$
• What is the effect of high energy electromagnetic waves on cells?

  They can cause cancer and cell damage