waves

• What are the two types of waves?

  • transverse waves
  • longitudinal waves
• How are oscillations arranged in a transverse wave?

  Perpendicular to the direction of energy transfer
• How are oscillations arranged in a longitudinal wave?

  Parallel to the direction of energy transfer
• What evidence shows that it is the wave that moves and not the water or air itself?

  Waves transfer energy without moving the medium
• What are the properties of waves?

  • Amplitude: maximum displacement from undisturbed position
  • Wavelength: distance between equivalent points on adjacent waves
  • Frequency: number of waves passing a point each second
  • Period: time for one complete wave cycle
• What is the formula for the period of a wave?

  Period [T] = 1/f
• What units are used for period and frequency?

  Period in seconds, frequency in hertz
• What does wave speed represent?

  Speed at which energy is transferred through the medium
• What is the wave equation?

  Wave speed = frequency × wavelength
• What are the units for wave speed, frequency, and wavelength?

  Wave speed in m/s, frequency in Hz, wavelength in m
• How do changes in velocity, frequency, and wavelength relate in sound wave transmission?

  • Changes in one affect the others
  • Increased frequency leads to shorter wavelength
  • Velocity changes with medium transition
• What should students be able to identify from given diagrams?

  Amplitude and wavelength
• What is a method to measure the speed of ripples on water?

  Use a ruler and stopwatch to time waves
• What is a method to measure the speed of sound waves in air?

  Use a timer and a known distance
• Why is it important to manipulate and control variables in experiments?

  To ensure valid and reliable results
• What should students be able to do in experiments?

  • Plan experiments to make observations
  • Produce or characterize substances
  • Test hypotheses and check data
• What is the dependent variable in an experiment?

  The variable measured for each change
• What is the independent variable in an experiment?

  The variable changed by the investigator
• What are control variables?

  Variables kept the same during the experiment
• What should students consider when selecting techniques and materials for experiments?

  • Appropriateness for the experiment's purpose
  • Accuracy and reliability of measurements
  • Health and safety considerations
• What is an accurate measurement?

  Close to the true value
• What is a repeatable measurement?

  Similar results by the same investigator
• What is a precise measurement?

  Measurements that cluster closely together
• What is a reproducible measurement?

  Similar results by different investigators
• What is random error?

  Results vary in unpredictable ways
• What is systematic error?

  Consistent difference from the true value
• What should be done with anomalous values?

  Examine and ignore if due to poor measurement
• What is required in practical activity 8?

  • Identify suitability of apparatus
  • Measure frequency, wavelength, and speed of waves
  • Use ripple tank and solid wave measurements
• What type of waves are electromagnetic waves?

  Transverse waves
• What do electromagnetic waves transfer?

  Energy from the source to an absorber
• How do electromagnetic waves travel in a vacuum?

  All travel at the same velocity
• How are electromagnetic waves grouped?

  • By wavelength and frequency
  • From long to short wavelength
  • From low to high frequency
• What part of the electromagnetic spectrum can our eyes detect?

  Visible light
• What are the practical applications of different electromagnetic waves?

  • Radio waves: television and radio
  • Microwaves: satellite communications, cooking
  • Infrared: electrical heaters, cooking
  • Visible light: fiber optic communications
  • Ultraviolet: energy-efficient lamps, tanning
  • X-rays and gamma rays: medical imaging and treatments
• What happens when radio waves are absorbed?

  They may create an alternating current
• What can changes in atoms result in?

  Generation or absorption of electromagnetic waves
• What can ultraviolet waves cause?

  Skin to age and increase cancer risk
• What are X-rays and gamma rays classified as?

  Ionising radiation
• What is radiation dose measured in?

  Sieverts
• What is required in practical activity 10?

  • Investigate infrared radiation absorption
  • Examine how it depends on surface nature