Ib Physics Hl Key Concepts

Front 1

Analogue Storage

Back 1

a record or a tape that suffers from noise and distortion, has a continuous signal

Front 2

Digital Storage

Back 2

A CD and a DVD, no deterioration, has a discrete signal, made up of binary signals

Front 3

CCD

Back 3

a microchip that can be used electronically to record an image

Front 4

Quantum Efficiency

Back 4

the number of electrons out and the number of protons in, it measures how efficient a CCD is

Front 5

Magnetification

Back 5

the image size on the CCD/actual image size in real world

Front 6

Polarised Wave

Back 6

The electric field only oscillates in one direction

Front 7

Unpoliarised Wave

Back 7

The electric field oscillates in random directions

Front 8

the Rayleigh Criterion

Back 8

Used when resolving images, specifically two objects where the minimum of one diffraction pattern falls on the maximum of the other.

Front 9

A Standing Wave/Maxima and Minima

Back 9

Formed by constructive interference of wave and reflected wave. Maximum=interference is constructive, waves are in phase. Minima= interference is destructive, waves are completely out of phase

Front 10

Diffraction of Light

Back 10

The spreading of light by an obstacle, for example a slit spreads light.

Front 11

Optically Active Substance

Back 11

A substance is one that rotates the plane of polarisation of light that passes through it.

Front 12

The Doppler Effect

Back 12

Come about because wave fronts from a moving source or incident on a moving observer appear to bunch together or spread apart depending on the type of motion involved.

Front 13

Frequencys

Back 13

When the observer moves towards the source a higher frequency is observed, and when the observer moves away form the source a lower frequency is observed.

Front 14

Resolution

Back 14

the separation limit between two objects being observed such that they are just discernable as two separate objects of just one blur. Limit=Rayleigh Criterion

Front 15

Polarity of the light/Polarized light waves

Back 15

The direction of the electric field vector. Light waves strike a surface in a place of incidence that are perpendicular to that plane of incidence will be reflected off the surface. These reflected waves are polarized.

Front 16

Polarizer/Analyzer

Back 16

Takes an input of natural light and transforms it into an output of polarized light/ Used as a reference polarizing axis to determine if the first polarizer is in fact a linear polarizer.

Front 17

Ideal Gas

Back 17

Very small particles, collisions between molecules and container are elastic. Have no inter molecular forces.

Front 18

Pressure

Back 18

The momentum change per unit time between the molecules and wall defines a force at the impact point of the wall. P=Force/Area, in Pascals

Front 19

Thermodynamic System

Back 19

the conditions under which heat can be transformed into mechanical work with a set of objects.

Front 20

Internal Energy

Back 20

the total kinetic energy of the all the molecules of a gas plus the potential energy associated with inter molecular forces between the molecules.

Front 21

Work done on or by the gas

Back 21

will change the state of the gas. If the gas is compressed, then work is done on the gas. If the gas expands, then work is done by the gas. Work is calculated as the area under a pressure against volume graph.

Front 22

Specific Heat Capacity

Back 22

Amount of energy required to raise the temperature of a unit mass of material by one degree Kelvin

Front 23

Heat Capacity

Back 23

The product of a mass times specific heat capacity, C=mc

Front 24

Specific Latent Heat

Back 24

The heat required to change a unit mass from a solid to a liquid or a liquid to a gas.

Front 25

de Brogile hypothesis

Back 25

Since light gave the same characteristic as a particle, all particles can therefore act like light and can produce waves, applies to all particles.

Front 26

Evidence for the quantization of nuclear energy levels

Back 26

Alpha particles have discrete values of kinetic energies and Gamma-ray photons have discrete energies, Beta particles are continuous

Front 27

The Schrodigner Model

Back 27

The hydrogen atom has a probability of finding an electron in a small region of space by calculating the amplitude of the wave function squared.

Front 28

The photoelectric effect

Back 28

When a light strikes a metallic surface, electrons may be emitted from the surface.

Front 29

Einstein's Model

Back 29

As the intensity of the light increase, more photons are striking the surface, emitting a larger number of electrons and producing a greater photo-current. Energy of the electrons does not change

Front 30

Work Function

Back 30

The minimum energy to free an electron/having the photo-electric effect happen of the surface.

Front 31

Natural Radioactive Decay

Back 31

Nuclei spontaneously emit particles, becoming different nuclei in the process. The process of nuclear decay is not affected by physical or chemical changes. Alpha, beta, and gamma emissions.

Front 32

Changes of State

Back 32

Isothermal= temperature doesn't change

Isobaric= pressure doesn't change

Isochoric= volume doesn't change

Adiabatic=everything changes except for internal energy

Front 33

Degraded Energy

Back 33

Energy that is transferred to the surroundings is no longer available to perform useful work.

Front 34

Non-renewable resources

Back 34

Cheap and emits CO2 emissions, coal and oil.

Front 35

Nuclear Energy

Back 35

Renewable, high energy density, difficult to dispose of

Front 36

Albedo

Back 36

The ratio of reflected to incident solar energy over the entire planet. Affected by the amount of Solar energy reflected by surface, earth's albedo depends on the season and latitude.

Front 37

Black-Body Radiation

Back 37

The radiation that is emitted by a perfect emitter.

Front 38

Coefficient of volume expansion

Back 38

the fractional change in volume per degree change in temperature.

Front 39

The Greenhouse Effect

Back 39

the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted form the planet's surface. The natural frequency of oscillation of CO2 in the infrared region.

Front 40

The Ampere

Back 40

The force between two long parallel currents. If two wires are 1 meter apart, then 1 amp of current flowing= the force to be 2x10^-7 N/m

Front 41

The Mass Spectrometer

Back 41

Particles have two different radii, two different masses, which means different elements, so isotopes were discovered.

Front 42

Induced emf

Back 42

The voltage across a circuit and is caused by any change in the magnetic environment of a coil of wire.

Front 43

Magnetic Flux

Back 43

The key to the process of using motion to create electric current. The quantity of the total flux is called the flux linkage.

Front 44

Faraday's Law

Back 44

The induced emf is equal to the negative rate of change of the magnetic flux.

Front 45

Lenz's Law

Back 45

Deduces the direction of the induced current in a closed loop due to a change in magnetic flux. The induced current will be in such a direction as to oppose the change in magnetic flux that created it.

Front 46

Alternating Current Generator (AC)

Back 46

Relative motion between a coil and a magnet will produce an induced current in the coil. The coil is rotated through a magnetic field which generates the ac current. As the rate of rotation increases, the frequency does too.

Front 47

Root Mean Square Voltage and Current

Back 47

The rms value of an alternating current (or voltage) is that value of the direct current (or voltage) that dissipates power in a resistor at the same rate. RMS=rating.

Front 48

Transformer

Back 48

A device that takes advantage of electromagnetic induction, it requires an input of alternating current.

Front 49

Average Velocity vs. Average Speed

Back 49

The rate at which an object changes position vs. rate of change of distance

Front 50

Instantaneous vs. Average Velocity

Back 50

Instantaneous is the velocity as a certain point which the average velocity is the amount of distance/time

Front 51

Inertia

Back 51

When the object is at rest or it is moving at a constant velocity. Property of matter that resists change in motion.

Front 52

Newton's First Law

Back 52

An object as rest or an object in constant velocity will remain at rest or at a constant velocity unless acted upon by an unbalanced force.

Front 53

Newton's Second Law

Back 53

The net force of an object is equal to the mass times the acceleration.

Front 54

Newton's Third Law

Back 54

For every action force there is an equal and opposite reaction force.

Front 55

What is true for an object to be in static or transitional equilibrium?

Back 55

The net force must be 0; the objects can either be at rest or it can be moving at a constant velocity, so no acceleration.

Front 56

Newton's Law of Universal Gravitation

Back 56

Two point masses will always attract each other with a gravitational force that is directly proportional to the product of the masses and inversely proportional to the square of the distance separating their centers.

Front 57

Gravitational Field Strength

Back 57

The force pet unit mass on a small mass placed at a point

Front 58

Gravitational Potential

Back 58

The work done to move unit mass form infinity to the point.

Front 59

Escape Speed

Back 59

The takeoff speed needed to reach a position of zero potential energy and kinetic energy.

Front 60

Kepler's 1st Law

Back 60

orbits of the planets are elliptical with the sun at one focus.

Front 61

Kepler's 2nd Law

Back 61

A line connecting the sun and a planet sweeps out equal areas in equal times. This means planets move faster when closer to the sun and slower when farther from the sun.

Front 62

Kepler's 3rd Law

Back 62

The square of the orbital period of a planet (T^2) is proportional to the cube of the semi-major axis (R^3) of T period of 1 revolution.

Front 63

Electric Field Strength

Back 63

The force per unit charge on a small positive test charge placed at a point in the field.

Front 64

Electrical Current

Back 64

The rate of flow per unit charge per unit time given at a point.

Front 65

Ohm's Law

Back 65

The Current will be directly proportional to the potential difference for a constant temperature.

Front 66

A Voltmeter

Back 66

Measures potential difference, should be connected in a parallel circuit and needs a high internal resistance.

Front 67

An Ammeter

Back 67

Measures current, should be connected in a series circuit and needs a low internal resistance.

Front 68

EMF

Back 68

the total work per moving charge available to an electric current. Batteries are not pure emf sources because they have internal resistance.

Front 69

Frequency of a Wave/Wave in general

Back 69

A wave energy only transforms energy not matter and the frequency is the number of oscillations per time. The speed of a wave is determined by the medium it moves through.

Front 70

Alpha radioactive decay

Back 70

A parent nucleus decays into a daughter nucleus and a helium nucleus (alpha particle). Can penetrate no more than a piece of paper.

Front 71

Beta negative radioactive decay

Back 71

A nucleus changes a neutron into a proton and an electron into an anti-neutron. Can penetrate several cm of aluminum.

Front 72

Gamma radioactive decay

Back 72

A nucleus with extra energy reduces its energy by emitting gamma rays. Can penetrate several cm of lead.

Front 73

Strong vs. Weak Nuclear Force

Back 73

Strong holds the nucleus together, but is very short ranged, while weak is responsible for the decay of a neutron into a proton.

Front 74

Mass Defect

Back 74

The difference between the mass of an isotope and it's mass number. The mass in the nucleus that is less than the mass of the individual neutrons and protons.

Front 75

Binding Energy

Back 75

The mass defect has been converted into the energy needed to keep the nucleus together and becomes this.

Front 76

Fission

Back 76

The splitting of a large nucleus into two smaller daughter nuclei, and neutrons. It is the basis for nuclear power plants.

Front 77

Fusion

Back 77

The combining of 2 small nuclei to form a larger nucleus. It is the basis for the sun and stars energy output.

Front 78

1st Law of Thermodynamics

Back 78

Change in Q= change in U and change in W, and heat always flows from hot to cold.

Front 79

2nd Law of Thermodynamics

Back 79

Entropy is the energy that is lost to the surroundings. The entropy of the universe can never decrease and the net entropy of a system is always positive.

Front 80

Simple Harmonic Motion

Back 80

An object is undergoing this motion if the acceleration of the object is directly proportional to its displacement and the acceleration is always directed towards the equilibrium position.

Front 81

Sinusodial

Back 81

Describes a smooth repetitive oscillation. It is named after the function sine of the graph.

Front 82

Transfer Waves

Back 82

Transfer energy in a direction perpendicular to the direction of the disturbance in the medium. A vibrating string is an example.

Front 83

Work

Back 83

Force acting over some amount of displacement to cause a change in energy (Joules or N/m)

Front 84

Angular Frequency (W)

Back 84

The rate at which an object in SHM undergoes its phase change, measured in radians per second.

Front 85

Damping

Back 85

Occurs when a force is applied that opposes the restoring force and decreases the Simple harmonic oscillator amplitude over time. 3 levels: lightly, critical, and over.

Front 86

Resonance

Back 86

Occurs when an obstacle force is applied at a frequency that matches the natural frequency of the oscillator. Makes the amplitude bigger.

Front 87

Longitudinal Wave

Back 87

A wave in which the energy flows in a direction parallel to the direction of particle oscillation. A sound wave.

Front 88

Redshift

Back 88

The change in the wavelength of the light divided by the wavelength that the light would have if the source was not moving.

Front 89

Blueshift

Back 89

Direct result of the Doppler Effect. The photon peaks appears to be closer together than they actually are, making the wavelength of light shorter as determined by the observer.