8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 1/12
No. Terms Definitions Equations
CHAPTER 1&2: PHYSICAL QUANTITIES AND UNITS & MEASUREMENT TECHNIQUES
1. Base Quantities2. Derived Quantities Quantities that are defined in two or more base quantities
3. Principle of
Homogeneity
When the units of all terms in an equations are the same, the
equations is said to be homogeneous
4. Avogadro Constant, NA Number of atoms in 0.012 kg of Carbon-12 NA=6.023x1023
mol-1
n !m
M
n !N
N A
5. Scalar Quantity Physical quantity that has only magnitude Speed, mass, density, pressure
6. Vector Quantity Physical quantity which has magnitude and direction Velocity, acceleration, force, momentum
7. Systematic Error Magnitude is constant in all reading
Cannot be eliminated by taking average
Zero error, reaction time, error due to assumption of physical conditions,
incorrect calibration
8. Random Error Readings to be scattered equally about the actual value Parallax error
9. Accurate Reading Measurement that is close to the actual value
10. Precise Reading Measurement that has very low or no random error
11. Uncertainty Smallest scale division of the instrument if the scale division 1mm
Half the smallest scale division of the scale division >1mm
CHAPTER 3: KINEMATICS
12. Distance Measure of how far an object has moved
13. Displacement The distance moved in a particular direction
14. Speed Distance moved per unit time
15. Velocity Rate of change of displacementAverage velocity =
( s(t
Instantaneous velocity =
dv
d t
16. Acceleration Rate of change of velocity Average acc =
v
t
Instantaneous acc =
d v
d t
17. Equations of Motion *For constant acceleration
v ! u at
s !1
2u v t
s ! ut 1
2at 2
v 2! u2
a s
e
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 2/12
18. Weight Gravitational force on body
W ! mg
*Acceleration due to gravity =
F
m
!m g
m
! g
*Unit for g: ms-1 or Nkg
-1
19. Force
Impulse
Rate of change of momentumForce,
F !m v u
t
Impulse,
F t !m v u
t
20. Projectile Motion
**
T ! t R
! 2t H
y
u x ! u cosU and
u y ! u sinU hence
y
a x ! 0and
a y ! g y Max R when
y Velocity at an instant (
v ! u at )
v x ! u cosU 0
v y
! u sinU g t
y Displacement at an instant (
s ! ut 1
2at 2 )
s x ! u cosU t 0
s y ! u sinU t 1
2 g t 2
y Hence, maximum height, H (
v 2! u2
a s&
v yH
! 0 )
02
! u sinU 2
2 g H
H !1
2
u sinU 2
g
y Time to reach H (
v ! u at &
v yH
! 0 )
0 ! u sinU g t
t H
!u sinU
g
y @t to fall back to the ground(
t R
! 2t H
!2u sinU
g) or (
s ! ut 1
2at 2)
0 ! u sinU T 1
2 g T 2
T !2u sinU
g
U ! 45r
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 3/12
y Max
s x /range,
R (
s ! ut 1
2at 2 but use
T ! t R ! 2t H )
R ! u cosU T 0
*Sub
T !2u sinU
g
R !u2 sin 2U
g
CHAPTER 4: DYNAMICS
21. Newtons First Law of
Motion
Every body continues in its state of rest or of uniform motion in a
straight line unless acted on by external forces to change that state
*Dynamic Equilibrium: A moving object experiencing zero net
force
*Static Equilibrium: An object at rest
y Inertia: Property of a body which resists change in motion or its
state of rest *depends on mass
y Mass: Property of a body which resists change in motion
y Gravitational field: Region where a mass experiences gravitational
force
y Gravitational field strength, g: Force per unit mass acting at that
point
y Linear momentum, p: Product of mass and velocity of an object
g ! F
m
p ! mv
22. Newtons Second Law of Motion
The rate of change of change of momentum of an object isproportional to the resultant force acting on it, & change in
momentum takes place in the direction of that force
F wd mv d t
F wma
F ! k ma
23. Newtons Third Law of
Motion
When body A exerts a force on body B, body B exerts a force equal on
magnitude but opposite in direction on A. The force is of the same
type.
*Characteristics of the A=R
y Act on different body
y Are of the same type of forcey Act at the same time
y Have the same magnitude but opposite direction
y Act along the same line of action
Action=Reaction
24. Principle of
Conservation of
Momentum
The total linear momentum of a system of forces is constant if no
external force act on the system
y Elastic collision
7 Ek conserved
y Inelastic collision
7 Ek not conserved*E lost as heat/ sound
y Inelastic *note the direction of
u1
,
u2
m1u1
m2u2
! m1v1
m2v2
y Elastic
m1u1
m2u2
! m1
m2 v
y Explosion
m1u1
m2u2
! 0
m1v1
! m2v2
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 4/12
y Explosion
25. Newtons Law of
Restitution
When two objects moving in same direction collide,
Relative v of approach= Relative v of separation y Relative v after = -e (relative v before)
v1 v2 ! e u1 u2
CHAPTER 5: FORCES
26. Fundamental Forces y Strong nuclear force
y Weak nuclear force
y Electromagnetic force
y Gravitational force
*Force also: product of the rate of change of mass and the change in
velocity
27. Couple A pair of equal and opposite forces which are parallel and whose line
of action do not coincide28. Moment of Forces
(about a point)
The product of the force and the perpendicular distance from the line
of action the force to the point
*F, take the magnitude, no need to x2
29. Torque Product of magnitude of a turning force and the perpendicular
distance of the line of action from an axis of rotation
*A specific type of moment
30. Principle of Moments For a system in equilibrium, the sum of moments of all forces acting
on the system about any point is zero
y Equilibrium: 7 F =0 and 7 Torque=031. Centre of Mass (of an
object/system)
The point at which an applied force acting at it produces acceleration
in the direction of the force but causes no rotational motion
32. Centre of Gravity The point where the weight appears to act
CHAPTER 6: WORK, ENERGY, POWER
33. Work, W Product of force and the displacement in the direction of the force
y 1J= Work done by 1N force as it acts through a distance 1m
along the line of force
W against gravityW =mgh
W by moving vehicle W =Ds *D=driving F
W due to expansion of gas where
34. Energy,E Capacity of doing work
*J or kWh
35. Kinetic Energy, Ek Energy possessed by a body due to its motion
36. Gravitational Potential
Energy, Ep
Energy possessed b an object due to its position in a gravitational
field/vertical ha=eight above the Earths surface
37. Electric Potential Energy (Of a charge Q at a point of p.d. V in an electric field )
38. Elastic Potential Energy Energy stored in a body due to deformation (stretching/compressing) From i.e. Hookes Law and F-e graph:
Moment ! F v Bd
W ! F s
W ! p v f vi
p !
F
A
E k
!1
2mv
2
E p
! m gh
E ! QV
F ! k e
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 5/12
W=¡
ve F x e
39. I¢
£
e¤ ¢ ¡
l E¢
e¤ ¥
y ¦ U S§ ̈
of all the ki¢
etic e¢
e¤ ¥
y and potential ene¤ ¥
y of the ato ̈
s and
molec§
les of a matte¤
y The Ep: Total ene©
y re
ired to maintain the position of
particles against i/m forces of both attraction and repulsion
in the matter
y The Ek: The average bulk energy of the vibrational
translational and rotational energies of all the particles in the matter
40. Principle of Conservation
of Energy
The total energy in a closed system is al
ays constant, or
Energy can neither be created nor destroyed but can be transferred
f rom one form to another
41. Po
er, P Rate at which work is being done Mechanical power against F resulting in v,
Electrical power dissipated when current I flow with p.d. v in a device
* Unit for P: W
*Energy Loss
Energy consumed by/lost in a device at p.d. v when Q charge pass
through
W=QV=Ivt
42. Efficiency
CHAPTER 9: PHASES
F MATTER
43. Kinetic Theory of Matter y Matter is made up of tiny discrete particles
y Particles are continuously in motion
44. Kinetic Theory of Gases y All molecules behave as identical, hard, perfectly elastic spheres
y Vol of molecules negligible compared to vol of gas
y Molecules move f reely in random motion
y Intermolecular forces are negligible y Time of collision is negligible compared to time between collision
W !1
2 F v e !
1
2k v e2 !
1
2 EA
e2
l
¨
ª©
¸
º¹
W
1
2
F
A
¨ª©
¸ º¹ A
¨ª©
¸ º¹
U ! E E p
P !!
t !
"
s
t !
"
v
P ! IV ! I 2 R ! V 2
R
Useful energy output
Total energy outputv100%
Useful power outputTotal energy output v100%
Area under ra h
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 6/12
45. Molecular Structure S L G
Spacing Closely,
regularlypacked
Slightly
further apart
Very far apart
Ordering Long-ranged
order spread
across a
lattice-space
Short-ranged
order
No order
Vol, shape F, F F, N N, N
Inter-atomic distance of S and L = 3v10-10
m
Inter-atomic distance of G = 33v10-10
m
46. Kinetic Model S L G
Motion
of
molec
Vibrate about
its mean
position
Random and
translational
motion
Translate
throughout
space at high
speed
I/m F High Attractive F,
cohesive F
Attractive F,
repulsive F
negligible
47. Density Mass per unit volume of a material*Unit for density: kg m
-3
48. Solids y Crystalline (metals, NaCl
compact regularly structured unit cellsionic/metallic
y Non-crystalline
Amorphous (glass
irregular atomic structures
weak Van der Waals
Polymeric (rubber, cellulose, proteins; plastic, polythene,
perspex)
large organic molecules arranged in disorderly manner
y Polycrystalline
Materials are made up of grains that are of many tiny crystalsograin size, softer the material/ q melting temp
y Non-crystalline
Amorphous: transparent - less compact structures, disorderly
arrangement of atoms
Polymeric: low strength and melting temp Van der Waals
tough - flexible structures
49. Pressure, P Average force acting normally per unit area
Depends on:
y No of molec per unit volume
y Speed of molec
y Frequency of collision
*scalar quantity *Unit of pressure=Nm-2
=Pa
50. Pressure in Liquids Force per unit area that is acting perpendicular to surface area
concerned where
*760 mm Hg=13600 x 9.8 x 0.76=1.013 x 105
Pa at 0rC
51. Pressure in Gases Pressure due to the force acting on the walls by the molecules of gasThe average rate of change momentum of the molecules
V !m
v
p !F
A
p ! V gh
V !m
v
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 7/12
CHAPTER 10: DEFORMATION OF SOLIDS
52. Deformation The change in shape caused by external forces.
-compressive
-tensile
53. Hookes Law The extension or compression e of a material by a constant load F is
directly proportional to the load applied provided the proportional
limit is not exceeded
F =ke
*Spring constant: Force per unit extension
y Parallel spring:
y Series spring:
54. Compressive strength The load or force applied per unit area on the material (under
compression)
55. Tensile strength The tensile stress is the load applied per unit extension resulted
(under extension)
56. Tensile Stress, W Force applied per unit cross-sectional area of the wire that is normal
to the direction of force
Results in a tensile strain set up within the wire
*Like pressure
*A=Area of wire=
57. Tensile Strain, I The extension e per unit length l of the wire
58. Youngs Modulus, E The ratio of tensile stress to the tensile strain is a constant for a
material provided the proportionality is not exceeded
***R/ship w k
k depends on:
-E, nature of material
-A & l, geometry & dimension of wire
where F=ke
*Unit for youngs Modulus, E = Pa
59. Elastic Strain Energy, W Work done in stretching the material
Equal to stored in the wire
*Stiff material: Material that resists deformation and requires a large
force to produce a small deformation
From F-e graph, A under curve = elastic strain energy, W
W= =
W= =
From F-e graph, gradient
k !F
e
§k ! k 1
k 2
1
§ k !
1
k 1
1
k 2
a
W !F
A
T d 2
4
I !e
l S
k !E A
l
@
E !W I
!Fl S
Ae
F !A E
l S
¨
ª©
¸
º¹e
k ! A E
l S
potential energy
elastic strain energy
1
2 F e
E Ae2
2l
1
2vF
Av A v
e
l
v l
1
2v str e ssv str ain v vol ume
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 8/12
Gradient = =spring constant,k
From stress-strain graph, A under curve= where
=
= = = strain energy per unit Vol
From stress-strain graph, gradient, m
Gradient = = E
60. Proportional limit Maximum point below which the extension of the wire is proportional
to the applied force
61. Elastic Limit Maximum point below which the wire can return to its original length
when the applied force is removed
62. Yield point Point at which the wore starts to exhibit plastic deformation
CHAPTER 15:WAVES
63. Progressive waves A disturbance that transfers energy outwards as a result of vibrations
of the particles of the medium
Transverse
Longitudinal
-Sound: 340ms-1
in air
Mechanical
Electromagnetic
-have same v in vacuum: = 3 x 108ms
-1
64. Stationary waves Waves where their wave profile do not move through the media of
vibration and the energy is localised
*The superposition of two wave trains with same
y Velocity
y Frequency
y Amplitude but in opposite direction
65. Displacement, x/y Distance of an oscillating particle from its mean equilibrium position
66. Amplitude, a Magnitude of the maximum displacement
67. Period, T Time taken for one complete oscillationwhere
68. Frequency, f Number of oscillations completed in one second*Unit of frequency: Hz
69. Wavelength, P Distance between two successive vibrating particles which are in the
same phase
70. Wave front A line/surface joining all the particles that have the same phase
#
F
( x
1
2W I
1
2W I
1
2vF
Ave
l S
1
Al S
1
2 F e
¨
ª©
¸
º¹
ener g y
vol ume
str e ss
str ain
c ! f P
[ !P
T !2T T
T !2T [
[ ! 2T f
f !1
T
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 9/12
71. Wave velocity, v Velocity of advance of the wave fronts
72.Particle velocity, /
Instantaneous velocity of a particle in the wave
73. Phase difference, The fraction of a cycle that two oscillating particles are out of step *Same phase = same direction, same displacement
74. Phase lag,=
y
If distance is away,
=T
y If distance is 2cm away, P=5cm
=
75. Wave intensity, I Amount of energy passing normally through unit area per unit time
y Intensity received at a point
The power P of the wave crossing the point per unitperpendicular cross-sectional area A
y
*r
2
=distance away from point source
y Intensity received at a pt
*P=power radiated by source
*A=area of spherical Wavefront
Power P radiated from source,
= =
76. Principle of
SuperpositionWhen two waves meet each other at a point, the resultantdisplacement is the sum of the separate displacements
77. Polarization of waves The process of confining the vibrations in one direction normal to the
direction of energy propagation
*Polaroid filter: Allows vibration only in one particular plane to pass through
CHAPTER 16: SUPERPOSITION
78. Coherent Constant phase difference
Same frequency
For better observation,
=a
79. Interference Superposition of two or more wave trains from coherent sources,
causing change in overall intensity
*Conditions: same type of wave, meet at a point, same direction of polarization
Const. Destr.
Path diff
v !P
T !
1
T
¨
ª© ¸
º¹P ! f P
dxd t
dy
d t
(N
N
N !2T
P x
k x
1
2P
N !2T
P
P
2
¨
ª© ¸
º¹
N !2T
5
4
5T
I w a2
I !
1
r 2
I !P
A!
P
4T r 2
@
I r 1v 4T r
1
2
I r 2v 4T r
2
2
I r 1
I r 2
!r 2
2
r 1
2
I r
!1
r 2
nP
2n 1 d
2
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 10/12
*x greater when: sources are close,far from source, high P
*x=separation of int.*
Phase diff
80. Diffraction The spreading of wave fronts through a narrow slit/opening/obstacle
by the superposition of secondary waves from the emerging wave
front
*a=size of aperture
For better observation,
a of the same order as the P
If a<P, diffraction more appreciable
81. Diffraction Grating Plate on which there is a large number of parallel, identical and veryclosely-spaced slits Spacing between slits, d=
82. Fundamental Frequency Lowest resonant frequency of vibration *Overtones have f which are integral multiples of it
CHAPTER 17: ELECTRIC FIELDS
83. Electric Field A region where a charge experiences electrostatic force Lines show direction of positive particles motion
84. Electric Field Strength, E The force per unit positive charge on a small test charge*Unit of E: NC
-1
where d=separation of plates *Unit of E: Vm-1
E= -potential gradient =
E due to point charges:
85. Electric Current, I Rate of flow of charged particles
*e-flow :-ve to +ve but conventional flow: +ve to -ve
*1C= the amount of charge that passes a point in a circuit when 1Acurrent flows for 1s.
(Instantaneous)
(Average)
86. Electric Potential, VE (at a
pt)
The work done in bringing the unit positive charge from infinity to the
point in a given electric field E
V E !W
q
CHAPTER 19: CURRENT OF ELECTRICITY
87. Potential
Difference,V(between 2
pt in E)
The work done in taking 1C of positive charge from A to B / Energy
transferred from electrical to other forms per unit charge
* 1V= p.d. between two points in a circuit if 1J of energy is transferred
when 1C of +ve charge pass from one point to another against thedirection of the electric field
W ! QV
W
! V I t
! I R I t
! V V
Rt
P !ax
D
sinU !P
a
asinU ! nP
1
N mm
E ! F
q
E !V
d
dv
dx
E ! F
q!
Q
4TI S r
2
I !d Q
d t
I ! Qt
2nT
2n 1 T
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 11/12
V !W
Q!P t
I t !P
I
Hence
P ! W t
* Unit: JC-1
or V
88. Energy and Power
liberated
y Energy dissipated /liberated by device, W
y Power of ea device i.e. energy liberated per second, P
* If its a passive resistor, all P dissipated as heat
W ! QV
!V I t
P !W
t
!QV
t
!I t V
t
! I V
*
P ! I 2 R
!V 2
Rtherefore
H ! I vt ! I 2 Rt !
V 2
Rt
89. Resistance, R (of a
conductor)
Ratio of the p.d. across it to the current passing through it
R !
V
I
*Unit: ;
90. Ohms Law Under constant physical conditions, the ratio of the p.d. across a
conductor to the current flowing through it is a constant
V
I ! constant
91. Resistivity, V (of a
material)
Numerically equal to the resistance of a sample of the material of unit
length and unit cross-sectional area
R !Vl A
*Unit for resistivity: ;m
92. Electromotive Force,
e.m.f. , E(of a source)
The energy transferred from other forms to electrical energy by it in
driving unit charge round a complete circuit / Ratio of power it generates to the current it delivers
y Terminal p.d. p.d. between the terminals of a cell when a
current is being delivered
E
!
W
Q / E=
!
P
I
93. Internal resistance, r (of
a cell)
Resistance due to the cells chemical constituents against the flow of
current
E=V+v = V+Ir = IR+Ir = I(R+r)
CHAPTER 20: D.C. CIRCUIT
94. Kirchoffs First Law In a network of circuits, the total current flowing into a junction is
equal to the total current flowing out of it
7 I in ! 7 I out
95. Kirchoffs Second Law Around a closed loop in a network of circuits, sum of e.m.f. is equal tosum of p.d.
(Applies conservation of energy)
7 E ! 7V
7 E ! 7 I R
96. Series
R ! R1
R2
R3
97. Parallel
1
R!
1
R1
!1
R2
!1
R3
I ! I 1
I 2
98. Potential Divider A circuit that divides the sources V into a number of p.d. across
various sections in the circuit
From 51,
V 1
! I R1and
V 2
! I R2
8/7/2019 PHY DEF half-updted
http://slidepdf.com/reader/full/phy-def-half-updted 12/12
V 1
!V
2
R2
¨
ª©
¸
º¹ R1
aV 1
V 2
!R1
R2
99. Potentiometer A circuit that is primarily used to measure p.d.
Used to
y Measure internal resistance, very small e.m.f. (thermocouple),
ammeter (and calibrate it)
y Measure and compare e.m.f.s, resistances
V w L
V 1
V 2
!L1
L2
CHAPTER 27: NUCLEAR PHYSICS
100. Atom Made up of a nucleus of positively-charged particles and uncharged
neutrons surrounded by negatively-charged electrons revolving in the
space around the nucleus
y d of nucleus= 10-15
m
y d of atom = 10-15
m
y charge of e-=1.6 x 10
-19C
y 1 atomic mass unit,u =
1
12mass of a C-12 atom =1.66x10
-27kg
101. Nucleon/Mass Number,
A
Total number of protons and neutrons in the nucleus in an atom
102. Proton/Atomic Number,
Z
Number of protons in the nucleus of an atom
103. Isotope Elements that have same proton number but different nucleon
number
104. Relative Atomic Mass, Ar
105. Mass-Energy
Conservation
Sum of the mass and energy of a closed system in similar units are
conserved
(mwill be accompanied by
( E
( E ! (mc 2where c= speed of light
106. Radioactive Decay The spontaneous and random emission of either E, F, or K
y E: He nucleus
2
4 H e
2
y F: [ F-, electron& F
+,positron] y
Z
A X p
Z 2
A 2Y
2
4 H e
2
y
0
1np
1
1 H 1
0e (electron) &
1
1 H p
0
1n
1
0e (positron)
107. Background Radiation Radiation due to surroundings and cosmic radiation entering the
Earths atmosphere108. Half-life The time taken for half the initial number of atoms to disintegrate