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A Level Physics - LVI B > Definitions > Flashcards

Flashcards in Definitions Deck (96)
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61

Electric Field Strength

Force per unit charge acting on a small positive test charge at a point in the field

62

Electric Potential

Work done per unit positive charge moving a small positive charge from infinity to that point in the field

63

Field

A region around an object where a force is exerted

64

Capacitance

The charge stored per unit pd of a capacitor

65

Dielectric

Material that increases the capacity of a parallel-plate capacitor to store charge when placed between the plates of the capacitor

66

Activity

The number of unstable radioactive nuclei that decay per second

67

Metastable State

An excited state of the nuclei of an isotope that last long enough after α or β emission for the isotope to be separated from the parent isotope

68

Atomic Mass Unit

One twelfth of the mass of a carbon-12 atom

69

Mass Defect

Mass of separated nucleons minus mass of nucleus

70

Binding Energy

The work that must be done to separate a nucleus into its constituent nucleons

71

Critical Mass

The minimum mass required to sustain a chain reaction of fission in a nuclear reactor

72

Fuel Rods (Nuclear Reactor)

Contains enriched uranium. Increased % of U-235 compared to uranium ore it's extracted from

73

Control Rods (Nuclear Reactor)

Made of cadmium or boron to absorb neutrons
Lifted in and out of the reactor to control the number of neutrons present and the rate of fission

74

Moderator (Nuclear Reactor)

Made of graphite or water
Slows down fission neutrons into one thermal energies, to increase the likelihood of absorption by U-235 nuclei

75

Coolant (Nuclear Reactor)

Water flows around the core, transferring heat away from the fuel, to be used to produce steam to drive a turbine

76

Angular Displacement

The angle moved through relative to a specific axis

77

Angular Velocity

The rate of change of angular displacement with respect to time

78

Centripetal Force

The force that makes an object move in a circle

79

Simple Harmonic Motion

Acceleration is proportional to the displacement of the object from equilibrium and is always directed towards the equilibrium position

80

Natural Frequency

The frequency of free oscillations of an oscillating system

81

Free Vibrations

Vibrations where there is no damping and no periodic force acting on the system, so the amplitude of the oscillations is constant

82

Forced Vibrations

Vibrations of a system subjected to an external periodic force

83

Resonance

The driving force matches the natural frequency of the system, leading to an increased amplitude of oscillation

84

Damping

The removal of energy from an oscillating system

85

Magnetic Flux Density

The magnetic force per unit length per unit current on a current carrying conductor at right angles to the field lines

86

Electromagnetic Induction

The generation of an emf when the magnetic flux linkage through a coil changes or a conductor cuts across magnetic field lines

87

Lenz's Law

The direction of the induced emf is always such as to oppose the change that causes the emf

88

Hall Probe

A device used to measure magnetic flux density

89

Magnetic Flux

The product of magnetic flux density and the area perpendicular to the field

90

Magnetic Flux Linkage

A measure of the magnetic flux of a coil of wire