waves

• What is a progressive wave?

  Transfers energy from one place to another
• What are the two categories of progressive waves?

  Transverse wave and longitudinal wave
• How do particles oscillate in a transverse wave?

  Perpendicular to the direction of propagation
• Give an example of a transverse wave.

  Water waves
• How do particles oscillate in a longitudinal wave?

  Parallel to the direction of propagation
• What is the maximum displacement from the equilibrium position called?

  Amplitude
• What is the wavelength in a wave?

  Minimum distance between two points in phase
• What is the time period of a wave?

  Time taken for one complete oscillation
• How is frequency defined?

  Number of cycles per unit time
• What is the unit for frequency?

  Hertz
• How are time period and frequency related?

  Time period is the inverse of frequency
• What is the formula for wave speed?

  Speed = distance over time
• What is the famous wave equation?

  Speed = frequency times wavelength
• What does phase difference describe?

  How far out of sync two points are
• How do you calculate phase difference?

  Phase difference = (distance/wavelength) * 360 degrees
• If two waves have peaks separated by 60 cm and a wavelength of 80 cm, what is their phase difference?

  270 degrees
• What happens when two waves differ by 180 degrees?

  They differ by half a wavelength
• What does an oscilloscope measure?

  Voltage and time intervals
• What does each square represent on an oscilloscope with a setting of 1 ms/cm?

  One millisecond
• If the oscilloscope shows a signal length of four squares, what is the time period?

  4 milliseconds
• How do you find the time period from an oscilloscope reading?

  Count the number of squares for one cycle
• If the oscilloscope is set to 2 V/cm and the amplitude is 1 square, what is the amplitude in volts?

  2 volts
• How do you calculate frequency from time period?

  Frequency = 1/time period
• If the time period is 4 ms, what is the frequency?

  250 hertz
• What are the three main properties of waves?

  1. Reflection: Change in direction at a boundary
  2. Refraction: Change in direction and speed in different media
  3. Diffraction: Spreading of waves through gaps or around obstacles
• What is the condition for reflection of a wave?

  Angle of incidence equals angle of reflection
• What happens to frequency during refraction?

  Frequency remains constant
• What is intensity in terms of waves?

  Power transmitted per unit area
• What is the equation for intensity?

  Intensity = power/area
• What are the units of intensity?

  Watts per square meter
• How does intensity vary with distance from a point source?

  Intensity decreases with distance
• What is the surface area of a sphere?

  4πr²
• How is intensity related to amplitude?

  Intensity is proportional to amplitude squared
• If the amplitude doubles, how does intensity change?

  Intensity increases four times
• What is the relationship between amplitude and intensity?

  Amplitude is proportional to the square root of intensity
• What are the properties of electromagnetic waves?

  • Travel through a vacuum
  • Speed of light: $3.0 \times 10^8 \text{ m/s}$
  • Transverse waves with oscillating electric and magnetic fields
• What are the longest wavelengths in the electromagnetic spectrum?

  Radio waves
• What is the wavelength range for microwaves?

  10 cm to $10^{-3} \text{ m}$
• What is the wavelength range for infrared radiation?

  $10^{-3} \text{ m} \text{ to } 7 \times 10^{-7} \text{ m}$
• What is the wavelength range for visible light?

  $7 \times 10^{-7} \text{ m} \text{ to } 4 \times 10^{-7} \text{ m}$