definition list
TRANSCRIPT
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Chapter 1: Introduction to Physics
Physical quantities QUANTITIES that are measurable
Base quantities PHYSICAL QUANTITIES that cannot be defined in terms of
other physical quantities but has its own definition
Derived quantities PHYSICAL QUANTITIES that are derived from base
quantities by multiplication or division or both
Scalar quantity QUANTITY which has only magnitude or size (time,
temperature, mass, volume, distance, density, power)
Vector quantity QUANTITY which has both magnitude or size and direction
(force, velocity, displacement, acceleration, momentum)
Systematic errors CUMULATIVE ERRORS that can be corrected, if the
errors are known. (zero error, incorrect calibration ofmeasuring instrument)
Random errors ERRORS that arise from unknown and unpredictable
variations in condition, and will produce a different error
Zero error ERROR that arises when the measuring instrument does not
start from exactly zero
Parallax error ERROR in reading an instrument because the observers eyes
and the pointer are not in a line perpendicular to the plane of
scale
Consistency ABILITY to register the same reading when a measurement is
repeated (improve eliminates parallax error, greater care,
not detective instrument)
Accuracy DEGREE to which a measurement represents the actual
value (improve repeat readings, avoid parallax/zero error,
high accuracy instrument)
Sensitivity ABILITY to detect quickly a small change in the value of a
measurement (thermometer thin wall bulb, narrowcapillary)
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Chapter 2: Forces and Motion
Distance how far a body travels during motion
Displacement CHANGE IN POSITION of an object from its initial position in a
specified direction
Speed RATE OF CHANGE of distance
Velocity RATE OF CHANGE of displacement
Mass AMOUNT of matter in the object
Acceleration RATE OF CHANGE of velocity
Inertia PROPERTY of matter that causes it to resist any change in its
motion or state of rest
Momentum PRODUCT of mass and velocity
Force pulling or a pushing ACTION on an object
Impulsive force LARGE FORCE which acts over a very short time
interval/RATE OF CHANGE in momentum
Gravity FORCE originated from centre of the Earth that pulls allobjects towards the ground
Free fall FALLING of an object without encountering any resistance from a
height towards the earth with an acceleration due to gravity
Forces in equilibrium An object is said to be in a state of equilibrium when
forces act upon an object and it remains stationary or moves
at a constant velocity
Resultant force SINGLE FORCE which combines two or more forces
which act on an object
WorkWork is done when a force causes an object to move in the direction of the
force.
Energy CAPACITY of a system to do work
Gravitational PE ENERGY STORED in the object because of its height above
the earth surface
Elastic PE ENERGY STORED in the object as a result of stretching or
compressing it
Kinetic energy ENERGY possessed by a moving object
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Power RATE at which work is done or energy is changed and
transferred
Efficiency ABILITY of an electrical appliance to transform energy from
one form to another without producing useless energy or
wastage
Elasticity PROPERTY of an object that enables it to return to its original
shape and dimensions after an applied force is removed
Spring constant FORCE needed to extend a spring per unit length
Elastic limit MAXIMUM STRETCHING FORCE which can be applied to an
elastic material before it ceases to be elastic
PRINCIPLE
Hookes Law
the force, F applied to a spring is directly proportional to the springs extension
or compression, x, provided the elastic limit is not exceeded.
Principle of conservation of energy
total energy in an isolated system is neither increased nor decreased by any
transformation. Energy cannot be created nor destroyed, but it can be
transformed from one kind to another, and the total amount stays the same.
Principle of conservation of momentum
in any collision or interaction between two or more objects in an isolated system,
the total momentum of the system will remain constant; that is, the total initial
momentum will equal the total final momentum.
Newtons first law of motion
a body will either remain at rest or continue with constant velocity unless it is
acted on by an external unbalanced force.
Newtons second law of motion
the acceleration a body experiences is directly proportional to the net force
acting on it, and inversely proportional to its mass. F =ma
Newtons third law of motion
to every action there is an equal but opposite reaction.
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Chapter 3: Forces and Pressure
Pressure FORCE acting normally on a unit surface area
Gas pressure FORCE per unit area exerted by the gas particles as they
collide with the walls of their container (due to the rate of change of
momentum)
Buoyant force NET FORCE acting upwards due to the difference between
the forces acting on the upper surface and the lower surface
PRINCIPLE
Law of Flotation
the weight of an object floating on the surface of a liquid is equal to the weight ofwater displaced by the object. (weight of object = weight of water displaced)
Archimedes principle
the buoyant force on a body immersed in a fluid is equal to the weight of the
fluid
displaced by that object (buoyant force = weight of water displaced)
Pascals Principle
a pressure applied to a confined fluid is transmitted uniformly in all directions
throughout the fluid.
Bernoullis principle
the pressure of a moving fluid decreases as the speed of the fluid increases, and
the
converse is also true.
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Chapter 4: Heat
Temperature DEGREE of hotness of an object
Thermometric property PHYSICAL PROPERTY of a substance which is
sensitive to and varies linearly with the temperature
change
Thermal equilibrium A STATE when heat transfer between the two objects
are equal and the net rate of heat transfer between the
two objects are zero
Heat capacity HEAT ENERGY required to raise its temperature
by 1C or 1 K
Specific heat capacity HEAT ENERGY required to produce 1C or 1 K rise intemperature in a mass of 1 kg.
Latent heat HEAT ABSORBED OR RELEASED when a substance
changes its state without a change in temperature is
calledthe latent heat of the substance
Specific latent heat of fusionHEAT ENERGY required to change 1 kg of a
substance from solid state to liquid state, without a
change in temperature
of vapourisation HEAT ENERGY required to change 1 kg of a substancefrom liquid state to gaseous state, without a change in
temperature at its boiling point
PRINCIPLE
Boyles Law
the pressure of a fixed mass of gas is inversely proportional to its volume
provided the
temperature of the gas is kept constant(PV = k)
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Pressure Law
the pressure of a fixed mass of gas is directly proportional to its absolute
temperature (in
Kelvin), provided the volume of the gas is kept constant (P/T = k)
Charles Law
the volume of a fixed mass of gas is directly proportional to its absolute
temperature (in
Kelvin), provided the pressure of the gas is kept constant
Chapter 5: Light
Refraction PHENOMENON where the direction of light is changed when it
crosses the boundary between two materials of different optical
densities as a result of a change in the velocity of light.
Apparent depth,d DISTANCE of the image from the surface of water (or
the boundary between the two mediums involved)
Real depth,D DISTANCE of the object from the surface of the water (or the
boundary between the two mediums involved)
Total internal reflection TOTAL REFLECTION of a beam of light at the
boundary of two mediums, when the angle of incidence
in the optically denser medium exceeds a specific
critical angle
Critical angle GREATEST ANGLE OF INCIDENCE in the optically denser
medium for which the angle of refraction, r = 90
Power of lens MEASURE OF ITS ABILITY to converge or diverge an
incident beam of light
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PRINCIPLE
Laws of Reflection
-the angle of incidence, i, is equal to the angle of reflection, r (i = r)
-the incident ray, normal and reflected ray will all lie in the same plane
Law of Refraction
-The incident ray and the refracted ray are on the opposite sides of the normal at
the point of incidence, all three lie
in the same plane
-Obey Snells law
Snells Law
The value of sin i/sin r is a constant
IMAGE CHARACTERISTICS
Virtual an image which cannot be projected (focused) onto a
screen
Real an image which can be projected (focused) onto a screen
Laterally inverted an image which left and right are interchanged
Upright an image which in vertical position
Diminished image formed is smaller than the object
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Magnified image formed is larger than the objec
Chapter 1 Waves
Waves
A TYPE OF DISTURBANCE produced by an oscillating or vibrating motion in whicha point or body moves back
and forth along a line about a fixed central point produces waves.
Wavefront
LINE OR PLANE on which the vibrations of every points are in phase and are at
the same distance from the source
of the wave.
In phase = same direction, same displacement
Transverse Wave
WAVE in which the vibration of particles in the medium is perpendicular to the
direction of propagation of the wave
(water waves, light waves, electromagnetic waves)
Longitudinal Wave
WAVE in which the vibration of particles in the medium is parallel to the direction
of propagation of the wave
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(sound waves, ultrasound)
Amplitude
MAXIMUM DISPLACEMENT form its equilibrium position
MEASURE of height of the wave crest or depth of the wave trough.
Period
TIME TAKEN to complete an oscillation, from one extreme point to the other and
back to the same position.
Frequency
NUMBER OF COMPLETE OSCILLATIONS made by a vibrating system in one second
Wavelength,
DISTANCE between successive points of the same phase in a wave
Damping
DECREASE in the amplitude of an oscillating system is called damping
(Internal damping: extension and compression of molecules
External damping: frictional force/ air resistance)
Resonance
Resonance occurs when a system is made to oscillate at a frequency equivalent
to its natural frequency by an
external force. The resonating system oscillates at its maximum amplitude.
Natural frequency
FUNDAMENTAL FREQUENCY of which an object vibrates. It is the frequency of a
system which oscillates freely
without external force
Reflection of wave
Reflection of wave occurs when a wave strike an obstacle
direction ; f = ; a = ; =
Refraction of wave
Refraction of wave occurs when a wave travel from one medium to another
f = ; v
;
; direction
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Diffraction of waves
PHENOMENON in which waves spread out as they passed through an aperture or
round a small circle
f = ; = ; speed = ; v ; direction
Interference of waves
SUPERPOSITION of two waves originating from two coherent sources
coherent = same frequency, amplitude and in phase
Constructive interference
Constructive interference occurs when the both crests or both troughs of both
waves coincide to produce a wave
with crests and troughs of maximum amplitude
Destructive interference
Destructive interference occurs when the crest of one wave coincides with the
trough of the other wave, thus
cancelling each other with the result that the resultant amplitude is zero.
Antinode
POINT where constructive interference occurs.
Node
POINT where destructive interference occurs
Electromagnetic waves
PROPAGATING WAVES in space with electric and magnetic components. These
components oscillate at right
angles to each other and to the direction of propagation of wave.
Monochromatic light
LIGHT with only one wavelength and colour
PRINCIPLE
Principle of superposition
Principle of superposition states that at any instant, the wave displacement of
the combined motion of any number of
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interacting waves at a point is the sum of the displacements of all the
components waves at that point.
Chapter 2 Electricity
Charge, Q
WORK DONE to move a unit of voltage in a circuit
Current, I
RATE of flow of charge
Potential difference, V
WORK DONE in moving one coulomb of charge from one point to another in an
electric field
Electric field
A FIELD in which electric charge experiences an electric force
A FIELD in which electric force acts in a particle with electric charge
Circuit
CLOSED LOOP through which charge can continuously flow
Resistance, R
RATIO of the potential difference across the conductor to the current flowing
through it
MEASURE of the ability of the conductor to resist the flow of an electric current
through it
Superconductor
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CONDUCTOR in which its resistance will suddenly become zero when it is cooled
below a certain temperature
called the critical temperature
Electromotive force (e.m.f.)
TOTAL ENERGY supplied by a cell to move a unit of electrical charge from one
terminal to the other through the
cell and the external circuit
Power rating
RATE at which it consumes electrical energy.
PRINCIPLE
Ohms Law
Ohms law states that the electric current,I flowing through a conductor is
directly proportional to the potential
difference across the ends of conductor, if temperature and other physical
conditions remain constant. That is, v is
directly proportional to r
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Chapter 4 Electronics
Thermoionic emission
EMISSION of electrons from hot metal surface
Work function MINIMUM ENERGY required to eject electrons from surface
Cathode ray
fast moving ELECTRONS travel in a straight line in vacuum
Cathode ray oscilloscope
measuring and testing INSTRUMENT used in study of electricity and electronics
Conductor
MATERIAL which allows current to flow through them
Semiconductor
MATERIAL whose resistance is between good conductor and insulator
Insulator
MATERIAL which does not conduct electric current
Junction voltage
POTENTIAL DIFFERENCE acting from n-type to p-type material of a diode across
the depletion layer
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Rectification
CONVERSION of a.c. to d.c. by diode
Smoothing
PROCESS where output is smoothed by connecting a capacitor across load that
acts as a reservoir and maintains
potential difference across load
Logic gates
ELECTRONIC SWITCHES with one or more inputs and one output.
Chapter 5 Radioactivity
Atom
An atom consists of a nucleus which is made up of protons and neutrons, with
electrons orbiting the nucleus.
Nuclide
TYPE of nucleus with particular proton number and nucleon number
Proton number
NUMBER of protons in the nucleus of an atom
Nucleon number
NUMBER of protons and neutrons in an atom
Isotopes
ATOMS of an element which have the same proton number but different nucleon
number(similar chemical
properties but differs in physical properties)
Radioactivity
SPONTANEOUS DISINTEGRATION of unstable nucleus into a more stable nucleus
with the emission of
energetic particles or protons
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Radioactive decay
PROCESS where an unstable nucleus becomes a more stable nucleus by emitting
radiations
Radioisotope
ISOTOPE that has unstable nucleus that tends to undergo radioactive decay
Half life
TIME TAKEN for the activity of atoms to fall to half its original value
TIME TAKEN for half the atoms in a given sample to decay
Nuclear fission
PROCESS involving the splitting of a heavy nucleus into two nuclei of roughly
equal mass and shooting out several
neutrons at the same time.
Nuclear fusion
PROCESS involving the fusion of two or more small and light nuclei come
together to form a heavier nucleus.
PRINCIPLE
Einsteins Principle of Mass-Energy Conservation
The change of energy is linked to the change of mass by the equation, E=mc2