physics definition Flashcards
1
Q
physical quantity
A
a quantity that is measurable
2
Q
base quantity
A
a physical quantity that cannot be derived in terms of other physical quantities
3
Q
example of base quantity
give 6
A
length, mass, time, electric current, temperature
4
Q
scalar quantity
A
a physical quantity which has ONLY magnitude
5
Q
vector quantity
A
a physical quantity which has magnitude and direction
6
Q
linear motion
A
motion in a straight line
7
Q
distance
A
total length of path of object moving from one location to another
8
Q
example of scalar quantity
A
distance, speed
9
Q
example of vector quantity
A
displacement, velocity, acceleration
10
Q
displacement
A
distance an object moves in a specific direction
11
Q
Newton’s first law of motion aka as
A
law of inertia
12
Q
inertia
A
every object continues its state of rest or in uniform speed unless acted upon by an external force
13
Q
momentum
A
a product of mass and velocity
14
Q
principle of conservation of momentum
A
the total momentum of a system is constant, if no external force acts on it
15
Q
explosion
A
a closed system which does not involve any external force
16
Q
what happens to total momentum in an explosion?
A
it is conserved
17
Q
force
A
push or pull
18
Q
Newton’s second law of motion
A
net force of an object is proportional to the rate of change of momentum
19
Q
Newton’s third law of motion
A
to every action, there is an equal but opposite reaction
20
Q
impulse
A
product of force and time interval during which the force acts
21
Q
impulsive force
A
rate of change of momentum during collision or explosion
22
Q
weight
A
the force of gravity which is exerted on it by Earth
23
Q
Kepler’s first law (law of ellipses)
A
orbits of planets are ellipses with the Sun in one of its focus
24
Q
Kepler’s second law (law of areas)
A
a line joining the planet with the Sun sweeps over equal areas in equal intervals of time as planet moves in orbit
25
from kepler's second law, the planet closer to the Sun
moves faster
26
kepler's third law (law of periods)
the square of period is directly proportional to the cube of orbital radius
27
escape velocity
the minimum velocity an object needs to overcome the gravitational pull of Earth and escape into outer space without falling back
28
geostationary satellite
a satellite in geostationary orbit around Earth on the equatorial plane
29
example of man made satellites
ISS Space Station
30
natural satellite
any object in space orbiting larger planets
31
thermal equilibrium
a state in which there is no net flow of heat between two bodies
the temperature of the two objects are equal
32
heat capacity, C
heat which is required to increase the temperature of the substance by 1 C
33
specific heat capacity, c
heat which is required to increase the temperature of 1 kg of substance by 1 C
34
latent heat
heat absorbed or given out at a constant temperature during change of phase
35
latent heat of vaporisation
heat energy released during condensation or boiling
36
latent heat of fusion
heat energy released during freezing or melting
37
specific latent heat
amount of heat needed to change phase of 1 kg of substance at a constant temperature
38
boyle's law
for a gas of fixed mass, the pressure is inversely proportional to its volume if temperature is constant
39
pressure law
for a gas of fixed mass, pressure is directly proportional to its absolute temperature if volume is constant
40
charle's law
for a gas of fixed mass, the volume of the gas is directly proportional to the absolute temperature of gas provided pressure of gas is constant
41
how to convert C to K
+ 273
42
longitudinal wave
wave where the particles of the medium vibrate in a direction that is parallel to direction of wave motion
43
transverse wave
wave where particles of medium vibrate in direction perpendicular to direction of wave motion
44
wavefront
a line which vibrations on it are in the same phase
45
wavelength
distance between two successive wavefront
46
amplitude
maximum displacement from its equilibrium position
47
period, T
time taken to complete one oscillation
48
frequency
number of complete oscillation made by a vibrating system in one second
49
damping
decrease of amplitude of an oscillating system
| during damping, an oscillating system loses its energy to surrounding
50
usually, the frequency of system remains
unchanged
51
resonance
happens in forced oscillation
| when external force equal to natural frequency of system oscillate with maximum amplitude
52
reflection
wave strikes an obstacle and undergoes change in direction of propagation
53
law of reflection states how many things
2
54
first, angle of incident is
equal to angle of reflection
55
secondly incident wave, reflected wave and normal lie on
the same plane
56
refraction
change in direction of propagation when a wave moves from one medium to another
57
refraction caused by
change of speed of wave moving from one medium to another
58
water wave refracts towards normal when
it travels from deep to shallow water
59
water wave refracts away from normal when
it travels from shallow to deep water
60
light wave refracts towards normal when
propagates to more optically dense medium
61
light wave refracts away from normal when
propagates to optically less dense medium
62
diffraction
spreading of wave when it travels through a small obstacle
63
principle of superposition
when 2 or more waves meet, total displacement at any point is the vector sum ion each individual wave at that point
64
coherent sources have _____ frequency and amplitude
same
65
acronym of electromagnetic spectrum
Romeo Made It Very Ugly, X Good
66
refraction
| definition following light and optics
bending of light ray while propagating from one medium to another with different optical density
67
law of refraction states that
value of sini/sinr is constant for light passing one medium to another
68
snell's law
value of sini/sinr is constant for light passing one medium to another
69
refractive index indicates
the medium's light bending ability
70
critical angle, c
angle of incidence in optically denser medium for which angle of refraction is 90
71
total internal reflection
total reflection of a beam of light at boundary
| when angle of incidence in optically denser medium exceeds the critical angle
72
what are the 2 conditions for Total internal reflection to occur
1. light ray must propogate from optically denser medium to less optically dense medium
2. angle of incidence must exceed critical angle
73
power of a lens measure
ability to deviate an incident ray of light
74
compound microscope
optical instrument used to view very small or fine objects
75
astronomical telescope
optical instrument used to view objects at a great distance
76
antinode
a point where 2 crests meet. constructive interference occurs
77
resultant force
the single force that represents the vector sum of 2 or more forces acting on an object
78
free body diagram
diagram that shows all forces acting on the object
79
resolution of forces
process of resolving a force into two components
80
forces in equilibrium
state an object is in when the forces acting on it produce zero resultant force
81
triangle of forces
show equilibrium of three forces acting on object
82
elasticity
property of material that enables object to return to its original shape and size after force acting on it is removed
83
hooke's law
extension of spring directly proportional to force applied on spring given the elastic limit is not exceeded
84
elastic potential energy
energy stored as a result of applying a force to deform an elastic object.
85
liquid pressure
is the increase in pressure at increasing depths in a liquid.
86
pressure
continuous physical force exerted on or against an object by something in contact with it.
87
actual pressure
addition of liquid pressure and atmospheric pressure
88
atmospheric pressure
pressure within the atmosphere of Earth.
89
atmospheric pressure aka
barometric pressure
90
fortin barometer
mercury barometer that measures atmospheric pressure to a high degree of accuracy
91
function of fortin barometer
measure atmospheric pressure at meteorological centres
92
function of aneroid barometer
obtain a quick reading of atmospheric pressure
93
aneroid barometers are suitable to be used in __
homes, ships and aeroplanes
94
how many units of pressure are there?
4
95
name the 4 units of pressure
Pa, mm Hg, m H2O, mbar
96
gas pressure
caused when gas particles hit the walls of their container.
97
manometer
a device to measure pressures
98
pascal's principle
pressure applied on an enclosed fluid is transmitted uniformly in all directions in fluid
99
hydraulic system
system that uses a liquid to transmit pressure
100
archimedes principle
an object which is partially or fully immersed in a fluid will experience a buoyant force equal to weight of fluid displaced
101
buoyant force
force acting upwards on an object immersed in a liquid
102
what is the one condition for buoyant force to occur
there is pressure difference between lower surface and upper surface of the object
103
hydrometer
a measuring instrument that measures density of liquids
104
ballast tanks
a compartment within a ship that holds water, to provide stability for a vessel
105
plimsoll line
a reference mark indicates the maximum depth the vessel may be safely immersed when loaded with cargo
106
Bernoulli's principle
when velocity of a fluid increases, the pressure in fluid decreases and vice versa
107
lift force
a mechanical force that is produced by the movement of an object through the air.
108
drag
air resistance that opposes movement
109
thrust
force produced by jet engines
110
electric field
region around a charged particle where any electric charge will experience a force
111
current
rate of flow of charge in a conductor
112
potential difference
the difference of electrical potential between two points
113
electric field strength at a given point
electric force acting on a unit positive charge placed at that point
114
resistance
a measure of the opposition to current flow in an electrical circuit
115
resistivity
a measure of a conductor's ability to oppose flow of electric current
116
non-conductor
a material that x conduct electricity
117
semiconductor
a material that has an electrical conductivity value between a conductor and an insulator
118
conductor
a material that conducts electricity
119
superconductors
a material that conducts electricity w/out resistance
120
critical temperature
temperature when the resistivity of a superconductor becomes zero
121
electromotive force
energy per unit electric charge that is imparted by an energy source
122
voltage drop
decrease of potential difference along the path of a current flowing in an electrical circuit
123
internal resistance
resistance caused by electrolyte in the dry cell
124
electrical energy
energy derived as a result of movement of electrons
125
power
amount of energy transferred
126
electromagnet
type of magnet in which the magnetic field is produced by an electric current
127
magnetic field
vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials
128
catapult field
resultant magnetic field produced by interaction between magnetic field from a current carrying conductor and from a permanent magnet
129
direct current
one-directional flow of electric charge
130
electromagnetic induction
production of an electromotive force across an electrical conductor in a changing magnetic field
131
magnetic flux
magnetic field lines that pass through a surface
132
alternating current
describes the flow of charge that changes direction periodically
133
transformer
changes voltage of a.c current
134
step up transformer
amplifies input voltage
135
step down transformer
decrease input voltage
136
ideal transformer
a transformer that does not experience energy loss, efficiency is 100%
137
eddy currents
loops of electrical current induced within conductors by a changing magnetic field in the conductor
