Waves in Air, Fluids & Solids

• What are the two types of waves mentioned in the study material?

  Transverse and Longitudinal

  
• How do waves transfer energy?

  By parts of the wave knocking nearby parts
• What is a transverse wave defined as?

  Waves where points along its length vibrate at 90 degrees to the direction of energy transfer

  
• In a transverse wave, how is energy transferred?

  Energy transfer is perpendicular to wave motion

  
• Can transverse waves move in liquids or gases?

  No, they cannot move inside liquids or gases
• What are some examples of transverse waves?

  Ripples on water, vibrations in a guitar string, S-waves, electromagnetic waves

  
• What is the highest point of a transverse wave called?

  The peak or crest

  
• What is the lowest point of a transverse wave called?

  The trough

  
• How are transverse waves represented in diagrams?

  As a single continuous line with a central line showing the undisturbed position

  
• What defines a longitudinal wave?

  Waves where points along its length vibrate parallel to the direction of energy transfer

  
• In a longitudinal wave, how is energy transferred?

  Energy transfer is in the same direction as wave motion

  
• Can longitudinal waves move in a vacuum?

  No, they cannot move in a vacuum
• What are the key features of a longitudinal wave?

  Compressions (close together) and rarefactions (spaced apart)

  
• What is an example of a longitudinal wave?

  Sound waves

  
• How are longitudinal waves represented in diagrams?

  As several lines showing the wave moving parallel to the direction of energy transfer

  
• What are the differences between transverse and longitudinal waves?

  • Transverse waves:
  • Vibrate at 90 degrees to energy transfer
  • Cannot move in liquids or gases
  • Examples: ripples, S-waves, electromagnetic waves
  • Longitudinal waves:
  • Vibrate parallel to energy transfer
  • Can move in solids, liquids, and gases
  • Examples: sound waves, P-waves

  
• How can wavefronts be represented for transverse and longitudinal waves?

  One line represents a peak or trough for transverse waves, and a compression or rarefaction for longitudinal waves

  
• What does the space between lines in wavefront diagrams represent?

  The wavelength of the wave
• What is amplitude defined as?

  The distance from the undisturbed position to the peak or trough of a wave
• What is the symbol for amplitude?

  A
• How is wavelength defined?

  The distance from one point on the wave to the same point on the next wave
• What is the symbol for wavelength?

  λ (lambda)

  
• How is frequency defined?

  The number of waves passing a point in a second

  
• What is the symbol for frequency?


  f

  
• How is the time period of a wave defined?

  The time taken for a single wave to pass a point
• What is the symbol for time period?

  T
• What is wave speed defined as?

  The distance travelled by a wave each second
• What is the symbol for wave speed?

  ν

  
• What is the wave equation?

  v = f × λ

  
• If a wave has a speed of $0.15 \text{ m/s}$ and a frequency of $0.5 \text{ Hz}$, what is the wavelength?


  $\lambda =$$\frac{v}{f} =$$\frac{0.15}{0.5} =$$0.30 \text{ m}$

  
• How do you calculate frequency from the time period?

  f = \frac{1}{T}

  
• What are the methods to measure the speed of sound?

  1. Measuring sound between two points
  2. Using echoes
  3. Using an oscilloscope

  
• In the first method of measuring sound, what do the two people do?

  One bangs wooden blocks while the other times the sound
• In the second method of measuring sound, what does the person do to listen for the echo?

  Claps two wooden blocks together
• In the third method of measuring sound, what is used to detect the sound?

  Two microphones connected to an oscilloscope
• What is the purpose of the oscilloscope in the third method?

  To determine the time at which the clap reaches each microphone

  
• What is the average time calculated for in the second method of measuring sound?

  The time taken for 20 claps
• How is the distance travelled by sound calculated in the second method?

  By multiplying the distance to the wall by 2

  
• What is the total distance travelled by sound during the 20 claps in the second method?

  (20 × 2 × 50) m
• What is the equation used to calculate the speed of sound in the first method?

  Speed = Distance ÷ Time