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A Level Physics - LVI B > Definitions > Flashcards

Flashcards in Definitions Deck (96)
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31

Ohm's Law

The current flowing through a metallic conductor is directly proportional to the potential difference across its ends, provided the temperature remains constant

32

Resistivity

The resistance of a piece of wire 1m in length and with a cross sectional area of 1m^2

33

Centre of mass

The point through which a single force on the body has no turning effect

34

Principle of conservation of linear momentum

The total linear momentum of a system of interacting bodies is constant, providing no external forces act

35

Work function

Minimum energy to liberate electron

36

Excitation

When an electrion takes in energy from a photon or collision and goes up an energy level

37

Ionisation

When an electron takes in enough energy to leave the atom

38

Progressive waves

Waves that move outwards from their source

39

Transverse waves

Each particle oscillates perpendicular to the direction of propagation to the wave

40

Longitudinal wves

Each particle oscillates parallel to the direction of propagation to the wave

41

Rarefied

More distance between particles than usual

42

Compression

Particles closer together

43

Mechanical waves

Oscillation of particles in a physical medium

44

Refraction

Change in path of light ray caused by a change in speed

45

Total internal reflection

The angle of incidence is greater than the critical angle

46

Diffraction

The spreading of waves when passed through a gap or round an obstacle

47

Kirchhoff's First Law

The sum of the currents leaving any junction is always equal to the sum of the currents that entered it

48

Kirchhoff's Second Law

The sum of potential differences across components of a series circuit is equal to the emf

49

Internal Resistance

Resistance inside a source of electrical energy; the loss of pd per unit current in the source when current passes through it

50

Potential Divider

Two or more resistors in series connected to a source of pd

51

Superconductor

A material that has zero electrical resistance below a critical temperature.

52

Gravitational Field Strength

The force per unit mass acting on a small test mass placed in the field

53

Gravitational Potential

The work done to move a unit mass from infinity to that point in a gravitational field

54

Kepler's First Law

All planets move about the Sun in elliptical orbits, having the Sun as one of the foci

55

Kepler's Second Law

A radius vector joining any planet to the sun, sweeps out equal areas in equal lengths of time

56

Kepler's Third Law

The square of the period of a planet's orbit is proportional to the cube of the mean radius of its orbit

57

Coulomb's Law

The magnitude of the force between two charges is proportional to the product of the charges and inversely proportional to the square of the distance between them

58

Electric Field

Region where a charged particle will experience a force

59

Gravitational Field

The region surrounding an object in which it exerts a gravitational force on any other object

60

Geostationary Satellite

A satellite that stays above the same point on the Earth's equator as it's period is 24 hours and has the same rotation direction