Waves
58 flashcards covering Waves for the MCAT Chem / Phys / Psych / Soc section.
Waves are disturbances that carry energy through a medium or space without transferring matter itself. They come in forms like sound waves, which vibrate air molecules, or light waves, which are electromagnetic and can travel through a vacuum. Key concepts include wavelength (the distance between peaks), frequency (how often a wave passes a point), amplitude (the wave's height), and speed, which depends on the medium. Understanding these basics helps explain phenomena from ocean tides to radio signals.
On the MCAT, waves appear mainly in the Chemical and Physical Foundations section, with questions testing your grasp of wave properties, behaviors, and applications in biology and medicine. You'll encounter multiple-choice problems on topics like refraction, interference, and the Doppler effect, often integrated with real-world scenarios such as ultrasound imaging. Common traps include mixing up formulas, like confusing velocity with frequency, or overlooking how waves interact with boundaries. Focus on mastering equations and visualizing wave patterns to avoid errors.
Practice sketching wave diagrams for quick insights.
Terms (58)
- 01
Wave
A wave is a disturbance that carries energy through a medium or space without transferring matter, characterized by properties like wavelength and frequency.
- 02
Transverse wave
A transverse wave is one where the medium's particles move perpendicular to the wave's direction of travel, such as light waves in a vacuum.
- 03
Longitudinal wave
A longitudinal wave is one where the medium's particles move parallel to the wave's direction of travel, like sound waves in air.
- 04
Wavelength
Wavelength is the distance between two consecutive points in phase on a wave, such as from crest to crest, and is denoted by the Greek letter lambda.
- 05
Frequency
Frequency is the number of wave cycles passing a point per second, measured in hertz, and determines the pitch of sound or color of light.
- 06
Amplitude
Amplitude is the maximum displacement of a wave's particles from their rest position, which relates to the wave's energy and intensity.
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Wave speed
Wave speed is the rate at which a wave propagates through a medium, calculated as the product of frequency and wavelength.
- 08
Period
Period is the time it takes for one complete wave cycle to pass a given point, and it is the inverse of frequency.
- 09
v = fλ
This formula relates wave speed to frequency and wavelength, where v is speed, f is frequency, and λ is wavelength, used for calculating wave properties.
- 10
Reflection
Reflection occurs when a wave bounces off a boundary or surface, following the law of reflection where the angle of incidence equals the angle of reflection.
- 11
Refraction
Refraction is the bending of a wave as it passes from one medium to another due to a change in speed, such as light entering water.
- 12
Diffraction
Diffraction is the bending or spreading of waves around obstacles or through openings, more pronounced when the obstacle size is comparable to the wavelength.
- 13
Interference
Interference is the interaction of two or more waves that results in a new wave pattern, either reinforcing or canceling each other.
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Constructive interference
Constructive interference happens when two waves align in phase, adding their amplitudes to create a wave with greater intensity.
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Destructive interference
Destructive interference occurs when two waves are out of phase, causing their amplitudes to cancel and reduce the resulting wave's intensity.
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Standing wave
A standing wave is a wave that appears stationary due to interference between incoming and reflected waves, with nodes and antinodes.
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Node
A node is a point on a standing wave with zero amplitude, where the medium does not move, such as at fixed ends of a string.
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Antinode
An antinode is a point on a standing wave with maximum amplitude, where the medium oscillates with the greatest displacement.
- 19
Resonance
Resonance is the amplification of wave amplitude when the frequency of an external force matches the natural frequency of a system.
- 20
Doppler effect
The Doppler effect is the change in frequency or wavelength of a wave relative to an observer moving toward or away from the source.
- 21
Sound wave
A sound wave is a longitudinal mechanical wave that travels through a medium by compressing and rarefying particles, enabling hearing.
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Electromagnetic wave
An electromagnetic wave is a transverse wave of electric and magnetic fields that can travel through vacuum, including light and radio waves.
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Speed of light
The speed of light is the constant speed at which electromagnetic waves travel in a vacuum, approximately 3.00 × 10^8 meters per second.
- 24
Huygens' principle
Huygens' principle states that every point on a wavefront acts as a source of secondary spherical wavelets, explaining wave propagation and diffraction.
- 25
Snell's law
Snell's law describes the relationship between the angles of incidence and refraction when a wave passes between media, given by n1 sin θ1 = n2 sin θ2.
- 26
Critical angle
The critical angle is the angle of incidence beyond which light undergoes total internal reflection when moving from a denser to a rarer medium.
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Total internal reflection
Total internal reflection is the complete reflection of a wave back into the original medium when the angle of incidence exceeds the critical angle.
- 28
Polarization
Polarization is the orientation of the oscillations in a transverse wave, such as light, in a specific direction perpendicular to its propagation.
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Double-slit experiment
The double-slit experiment demonstrates wave interference by passing light through two slits, producing a pattern of bright and dark fringes.
- 30
De Broglie wavelength
The de Broglie wavelength is the wavelength associated with a particle, calculated as h divided by momentum, linking particle and wave properties.
- 31
Uncertainty principle
The uncertainty principle states that there is a fundamental limit to knowing both the position and momentum of a particle simultaneously, arising from wave-particle duality.
- 32
Alpha waves
Alpha waves are brain waves with frequencies between 8 and 12 Hz, associated with relaxed wakefulness in EEG recordings.
- 33
Beta waves
Beta waves are brain waves with frequencies between 12 and 30 Hz, linked to active thinking and alertness in EEG patterns.
- 34
Theta waves
Theta waves are brain waves with frequencies between 4 and 8 Hz, often occurring during light sleep or deep relaxation.
- 35
Delta waves
Delta waves are the slowest brain waves, with frequencies below 4 Hz, typically seen during deep sleep stages.
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Gamma waves
Gamma waves are brain waves with frequencies above 30 Hz, associated with higher cognitive functions like problem-solving.
- 37
Wavefront
A wavefront is a surface over which the phase of a wave is constant, such as a straight line for plane waves or a sphere for point sources.
- 38
Ray diagram
A ray diagram is a graphical representation of light paths, showing how rays reflect or refract to form images in optical systems.
- 39
Lens formula
The lens formula relates object distance, image distance, and focal length for a lens, given by 1/f = 1/u + 1/v.
- 40
Mirror equation
The mirror equation relates object distance, image distance, and focal length for a mirror, expressed as 1/f = 1/u + 1/v.
- 41
Superposition principle
The superposition principle states that when two or more waves overlap, the resultant wave is the sum of the individual waves' displacements.
- 42
Beat frequency
Beat frequency is the rate at which the amplitude of combined waves varies, equal to the difference between their frequencies.
- 43
Simple harmonic motion
Simple harmonic motion is periodic motion where the restoring force is directly proportional to the displacement, underlying many wave phenomena.
- 44
String wave
A string wave is a transverse wave that travels along a taut string, with speed determined by tension and linear density.
- 45
Sound intensity
Sound intensity is the power per unit area carried by a sound wave, measured in watts per square meter and related to perceived loudness.
- 46
Decibel scale
The decibel scale is a logarithmic measure of sound intensity level relative to a reference, used to quantify sound loudness.
- 47
Ultrasound
Ultrasound refers to sound waves with frequencies above 20,000 Hz, beyond human hearing, used in medical imaging.
- 48
Infrasound
Infrasound consists of sound waves with frequencies below 20 Hz, often produced by natural events like earthquakes.
- 49
Light as an EM wave
Light is an electromagnetic wave that consists of oscillating electric and magnetic fields, traveling at the speed of light in a vacuum.
- 50
Radio waves
Radio waves are long-wavelength electromagnetic waves used for communication, with frequencies from about 3 kHz to 300 GHz.
- 51
Microwaves
Microwaves are electromagnetic waves with wavelengths from about 1 mm to 1 m, used in cooking and wireless technology.
- 52
Infrared radiation
Infrared radiation is electromagnetic waves just beyond red light, with wavelengths from 700 nm to 1 mm, felt as heat.
- 53
Visible light
Visible light is the portion of the electromagnetic spectrum that humans can see, with wavelengths from about 400 to 700 nm.
- 54
Ultraviolet radiation
Ultraviolet radiation is electromagnetic waves with wavelengths shorter than visible light, from about 10 to 400 nm, causing sunburn.
- 55
X-rays
X-rays are high-energy electromagnetic waves with wavelengths from 0.01 to 10 nm, used in medical imaging to penetrate tissues.
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Gamma rays
Gamma rays are the highest-energy electromagnetic waves, with wavelengths less than 0.01 nm, emitted in nuclear reactions.
- 57
Dispersion
Dispersion is the separation of light into its component colors due to varying speeds of different wavelengths in a medium, as in a prism.
- 58
Rainbow formation
Rainbow formation results from the dispersion, refraction, and reflection of sunlight in water droplets, creating a spectrum of colors.