Waves and electromagnetic spectrum

• Transverse waves are defined as waves that vibrate or oscillate perpendicular to the direction of energy transfer
• Transverse waves transfer energy, but not the particles of the medium
• Transverse waves can move in solids and on the surfaces of liquids, but not inside liquids or gases
• Some transverse waves, like electromagnetic waves, can move in solids, liquids, gases, and in a vacuum
• Examples of transverse waves include ripples on the surface of water, vibrations in a guitar string, S-waves (a type of seismic wave), and electromagnetic waves (such as radio, light, X-rays, etc)
• Longitudinal waves are defined as waves where the points along its length vibrate parallel to the direction of energy transfer
• Longitudinal waves transfer energy, but not the particles of the medium
• Longitudinal waves can move in solids, liquids, and gases, but not in a vacuum
• Key features of longitudinal waves are compressions (points close together) and rarefactions (points spaced apart)
• Examples of longitudinal waves include sound waves, P-waves (a type of seismic wave), and pressure waves caused by repeated movements in a liquid or gas
• Wave vibrations can be shown on ropes (transverse) and springs (longitudinal)
• Transverse waves have peaks and troughs, while longitudinal waves have compressions and rarefactions
• In transverse waves, vibration is perpendicular to the direction of energy transfer, while in longitudinal waves, vibration is parallel to the direction of energy transfer
• Transverse waves can travel through solids and on the surface of liquids, while longitudinal waves can travel through solids, liquids, and gases
• All waves transfer energy and information, but not matter
• Objects floating on water demonstrate that waves only transfer energy and information, not matter
• Transverse waves are seen on the surface of water, where objects like a toy duck bob up and down as waves pass underneath
• When a wave travels between two points, no matter actually travels with it, the points on the wave just vibrate back and forth about fixed positions
• Amplitude is the distance from the undisturbed position to the peak or trough of a wave
• Amplitude is measured in meters (m) and represents the maximum or minimum displacement from the undisturbed position
• Wavelength is the distance from one point on the wave to the same point on the next wave
• In a transverse wave, wavelength can be measured from one peak to the next peak, while in a longitudinal wave, it can be measured from the center of one compression to the center of the next
• Frequency is the number of waves passing a point in a second
• Frequency is measured in Hertz (Hz)
• The time period of a wave is the time taken for a single wave to pass a point
• Time period is measured in seconds (s)
• The wave equation is used to calculate wave speed, where v = wave speed in meters per second (m/s), f = frequency in Hertz (Hz), and λ = wavelength in meters (m)
• The wave speed equation may need to be rearranged using a formula triangle
• The equation relating frequency and time period is T = 1 ÷ f, where T = time period in seconds (s) and f = frequency in Hertz (Hz)
• This equation can be used to calculate the time period of a wave based on its frequency
• The wave speed equation can be applied and rearranged to calculate properties of waves such as wave speed, frequency, and time period
• The wave equation applies to all types of waves, including sound waves and electromagnetic waves
• The speed of a wave can be calculated using the equation v = f × λ, where v = wave speed, f = frequency, and λ = wavelength
• This equation can be used to find the speed of waves based on their frequency and wavelength
• When stating equations, make sure to draw diagrams and describe the parts of the wave for better understanding and full marks in exams
• The Doppler Effect is defined as the apparent change in wavelength and frequency of a wave emitted by a moving source
• The Doppler Effect can be observed in various scenarios whenever sources of waves move
• Examples of the Doppler Effect include the change in frequency of sound waves emitted by ambulance or police sirens as they pass by, and galaxies in outer space emitting light waves that appear redder than normal as they move away from us
• When a stationary object emits waves, the waves spread out symmetrically
• If the object emitting waves begins to move, the waves can get squashed together at one end and stretched at the other end