1
Q
Equilibrium Position
A
The position where the object would rest if all energy was removed from the system.
2
Q
Oscillations
A
Periodic back and forth motion.
3
Q
What is always the center of an oscillation?
A
The equilibrium Position
4
Q
Displacement
A
How far something is from the equilibrium position.
5
Q
Amplitude
A
The distance between the crest (or trough) of a wave and its equilibrium position.
6
Q
Time Period (T)
A
The time taken to complete a full cycle. (seconds)
7
Q
Frequency (f)
A
The rate at which something occurs over a particular period of time or in a given sample. (Hz)
8
Q
Angular frequency (w)
A
The angle covered by a simple harmonic motion oscillator per second. (rad s−1)
9
Q
Simple harmonic motion (SHM)
A
- Oscillations around an equilibrium position where the displacement is proportional to the negative acceleration.
- Repeated motion around an equilibrium position where the acceleration of the object is proportional to its displacement, but in the opposite direction.
10
Q
What factors affect the time period of a simple pendulum and what factor does not?
A
Affect: Length, gravitational force
Don’t affect: Mass
11
Q
What factors affect the time period of a mass-spring system and what factor does not?
A
Affect: Mass, spring constant
Don’t affect: Amplitude, gravity
12
Q
What type of energy does a pendulum have at it’s peak?
A
All of the pendulum’s energy isgravitational potential energy.
13
Q
What type of energy does a pendulum have at it’s equillibirum position?
A
All of its energy has been transferred tokinetic energy.
14
Q
What type of potential energy is present in a horizontal mass–spring system?
A
Elastic potential energy, which transfers to kinetic energy during motion.
15
Q
What types of energy are present at thetopof a vertical mass–spring system?
A
Gravitational potential energy andelastic potential energy.
16
Q
What type of energy is present at thebottomof a vertical mass–spring system?
A
Elastic potential energy
17
Q
What is the Law of Conservation of Energy regarding a system with no resistive forces?
A
No energy is lost, and thetotal energy of the system remainsconstant.
18
Q
Mechanical waves
A
A wave that needs a medium to travel through.
19
Q
Wave
A
Anoscillationthat transfersenergybut not matter.
20
Q
Longitudinal waves
A
A wave whose particles oscillate parallel to the direction of energy transfer.
21
Q
Transverse waves
A
A wave whose particles oscillate at right angles to the direction of energy transfer.
22
Q
Wavelength
A
The distance between adjacent identical points on a wave, for example, two crests or two compressions.
23
Q
Which type of wave does not have crests or troughs?
A
Longitudinal waves
24
Q
Compressions of longitudinal waves
A
Areas of a longitudinal wave where the particles have a higher density,
25
Rarefactions of longitudinal waves
Areas of a longitudinal wave where the particles have a lower density.
26
Sound waves
- Longitudinal waves
- Mechanical waves and need a medium to travel through.
27
28
Adiabatic processes
A thermodynamic process in which no thermal energy is transferred between the system and its surrounding.
29
What two things are very close to being adiabatic processes?
Compressions and rarefactions
30
Electromagnetic waves
An oscillation in electric and magnetic fields. It is not a mechanical wave and does not need a medium to travel through.
31
What type of wave can travel through a vacuum?
Electromagnetic
32
Electromagnetic waves with shortest wavelengths and the highest frequencies
Gamma rays
33
Electromagnetic waves with longest wavelengths and the lowest frequencies
Radio waves
34
Wavefronts
Imaginary surfaces that connect points on a wave that are in phase
35
Rays
Imaginary lines that show the direction of energy transfer in the wave as well as the direction of propagation.
36
Rays in a plane wave
All the rays are parallel to each other, and we track a single ray.
37
Rays in a spherical wave
The rays are along radial directions and are divergent.
38
Reflection
A wave encounters a boundary between two different media and bounces back. The angle of reflection is equal to the angle of incidence.
39
Law of reflection
The angle of incidence (the angle between the incident wave and the normal to the surface) is equal to the angle of reflection (the angle between the reflected wave and the normal to the surface).
40
Rules for drawing wavefronts on a ray diagram for reflection (4)
1. Wavefronts are always perpendicular to rays.
2. In a single medium, the distance between one wavefront and the next is constant (and equals the wavelength).
3. Reflection does not change the wavelength of a wave.
4. Wavefronts do not pass through a mirror.
41
Refraction
The change in direction of a wave when it moves from one material to another at an angle, due to the difference in velocity of the waves in the two materials.
42
Rules for drawing wavefronts on a ray diagram for refraction (2)
1. Wavefronts are always perpendicular to rays.
2. In a single medium, the distance between one wavefront and the next is constant (and equals the wavelength).
43
Transmission
When a wave passes across a boundary between two different media and continues to travel through the new medium.
44
Diffraction
The spreading of waves as they travel around a body or through an aperture.
45
Refractive index
A measure of how much a medium can slow down light waves. The ratio of the speed of light in a vacuum to the speed of light in the medium.
46
Use of Snell's law
to describe the relationship between the angle of incidence, and the angle of refraction.
47
Snell's Law
An equation that describes the angle of incidence and angle of refraction as light (or other waves) is refracted through a boundary between two media that have different refractive index.
48
Critical angle
The angle of incidence at which light is refracted along the boundary between a medium with a greater refractive index and a medium with a smaller refractive index.
49
What does the critical angle depend on?
The refractive index of each medium.
50
Total internal reflection
When the angle of incidence is greater than the critical angle at the boundary between a medium with a greater refractive index and a medium with a smaller refractive index. Light is completely reflected back into the medium with the greater refractive index.
51
Conditions for total internal reflection (2)
1. The light must be passing from a medium with a higher refractive index into a medium with a lower refractive index.
2. The angle of incidence must be greater than the critical angle.
52
Superposition of waves
Two waves meet and their displacements add together at every point in space to produce a combined wave with a resultant displacement.
53
Constructive interference
Occurs when two waves meet in phase (crests meet crests and troughs meet troughs), resulting in a wave with increased amplitude.
54
Destructive interference
Occurs when two waves meet out of phase (crests meet troughs), resulting in a wave with decreased or zero amplitude.
55
Path difference
The difference in distance that two waves travel from a source to a given point.
56
What does the path difference have to be for constructive interference to occur?
The path difference between two waves is a whole number of wavelengths – the crest (and trough) of one wave meets the crest (and trough) of another wave.
57
What does the path difference have to be for destructive interference to occur?
The path difference between the waves is a half-integer multiple of the wavelength.
58
What happens to amplitude with constructive interference?
Amplitude increases
59
What happens to amplitude with destructive interference?
Amplitude decreases
60
Summary of the double-slit experiment
In the double-slit experiment, a monochromatic coherent light source (such as a laser) emits light waves towards a screen with two narrow slits. When the light waves pass through these slits, they act as two coherent light sources. The light waves interfere, creating an interference pattern on the optical screen. The interference pattern consists of alternating dark and light fringes (bands).
61
In the double-slit experiment where is constructive interference occuring?
Light fringes (maxima)
62
In the double-slit experiment where is destructive interference occuring?
Dark fringes (minima)
63
Antinodes
The point of a standing wave where amplitude of oscillation is at a maximum.
64
Nodes
A point of a standing wave where amplitude of oscillation is zero.
65
How do antinodes and nodes move in a standing wave?
Nodes and antinodes do not move along the wave, but always stay in the same horizontal position, with the antinodes only oscillating vertically
66
Boundary conditions for standing waves
The conditions at the ends of a string or pipe. For a string, an end can be fixed or free. For a pipe, an end can be open or closed.
67
Equations for wavelength in a string with two fixed boundaries. (harmonics 1- 4)
1st: 2L
2nd: 1L
3rd: (2/3)L
4th: (1/2)L
68
What is happening with the particles at the open end of a pipe?
The particles at the open ends of the pipe oscillate with maximum displacement. They are at the antinodes of the wave.
69
What is happening with the particles at the closed end of a pipe?
Particles at the closed end are not vibrating at all (forming a node).
70
Equations for wavelength in an open–closed pipe.
1st: 4L
2nd: (4/3)L
3rd: (4/5)L
4th: (4/7)L
71
The general equation for wavelength in an closed pipe.
2L/n
72
The general equation for wavelength in an open–closed pipe.
4L/n
73
Natural frequency
The frequency at which a system vibrates or oscillates when it is disturbed.
74
Driving frequency
The frequency of the oscillator supplying energy to the system.
75
Resonance
When the frequency of the energy incident on a system is equal to that of the system’s natural frequency, it vibrates at maximum amplitude.
76
Resonant frequency
The frequency at which the oscillations of an object gain the greatest amplitude.
77
Damping
Techniques used to restrain and reduce oscillations and vibrations. Loss of energy due to resistive forces.
78
Light damping
There is a small amount of damping only. The system will continue to oscillate, but the amplitude of the oscillations decreases exponentially over time.
79
Heavy damping
There is a large amount of damping. The system gradually dissipates all its energy. It does not oscillate, but returns very slowly to its equilibrium state.
80
Critical damping
There is a very large amount of damping. The system returns to its equilibrium state as quickly as possible without any oscillations.
81
Dopple effect
The change in the observed frequency of a wave based on the relative motion between the source and the observer. This change in observed frequency is from the perspective of the observer and not the source. If the source was observing itself, it would not notice any change in observed frequency.
82
Double Doppler effect
When a moving source produces a wave that reflects off a moving object and is received by the source again.
83
What does the Doppler effect depend on?
The Doppler effect depends on the relative velocity between the source and the observer.
84
Spectral lines
The wavelengths of light emitted by different elements losing electrons/ energy.
85
Where do spectral lines come from?
The light emitted by a star.
86
What color is the emitted when the light wave is moving away from us, the wavelength appears to be longer?
Red
87
What color is emitted when the light wave is moving towards us, the wavelength appears to be shorter?
Blue
88
Blue shift
A decrease in the electromagnetic wavelength of light caused by the motion of an object getting closer to the observer. Shorter wavelengths of visible light are shifted towards the blue region of the visible spectrum.
89
Red shift
An increase in the electromagnetic wavelength of light caused by the motion of an object getting further away from the observer. Longer wavelengths of visible light are shifted towards the red region of the visible spectrum.
IB SL Physics
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