(C) Yeo Yih Tang 2009. Mail: [email protected] 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
Scientific notation/
standard form POWERS of the base number 10 to show a very large or small number Prefixes GROUP OF LETTERS placed at the beginning of a word to modify its meaning,
which act as multipliers
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)
Error DIFFERENCE between actual value of a quantity and the value obtained in measurement
Systematic errors CUMULATIVE ERRORS that can be corrected, if the errors are known. (zero error, incorrect calibration of measuring instrument)
Random errors ERRORS that arise from unknown and unpredictable variations in condition, and will produce a different error every time. Random errors are caused by factors that are beyond the control of observers.
(human limitations, lack of sensitivity, natural errors, wrong technique) Zero error ERROR that arises when the measuring instrument does not start from exactly
zero
Parallax error ERROR in reading an instrument because the observer’s eyes and the pointer are not in a line perpendicular to the plane of scale
Measurement PROCESS of determining value of a quantity using a scientific instrument with a standard 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, narrow capillary)
Inferences EARLY CONCLUSION that you draw from an observation or event using information that you already have on it
Hypothesis GENERAL STATEMENT that is assumed to be true regarding the relationship between the manipulated variable and responding variable
(C) Yeo Yih Tang 2009. Mail: [email protected] 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 MEASURE of an object’s inertia
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 all objects 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
Work Work 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
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
(C) Yeo Yih Tang 2009. Mail: [email protected] PRINCIPLE
Hooke’s Law Hooke’s law states that the force, F applied to a spring is directly proportional to the spring’s extension or compression, x, provided the elastic limit is not exceeded. Principle of
conservation of energy
Principle of conservation of energy states that 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
The principle of conservation of momentum states that, 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.
Newton’s first
law of motion Newton’s first law of motion states that a body will either remain at rest or continue with constant velocity unless it is acted on by an external unbalanced force.
Newton’s second law of motion
Newton’s second law of motion states that the acceleration a body experiences is directly proportional to the net force acting on it, and inversely proportional to its mass. F =ma
Newton’s third
(C) Yeo Yih Tang 2009. Mail: [email protected] 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 Law of floatation states that the weight of an object floating on the surface of a liquid is equal to the weight of water displaced by the object.
(weight of object = weight of water displaced)
Pascal’s Principle Pascal’s principle states that a pressure applied to a confined fluid is transmitted uniformly in all directions throughout the fluid.
Archimedes’
principle Archimedes’ principle states that 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)
Bernoulli’s
(C) Yeo Yih Tang 2009. Mail: [email protected] 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 1°C or 1 K
Specific heat
capacity HEAT ENERGY required to produce 1°C or 1 K rise in temperature in a mass of 1 kg. Latent heat HEAT ABSORBED OR RELEASED when a substance changes its state without a
change in temperature is called the latent heat of the substance Specific latent
heat of fusion HEAT ENERGY required to change 1 kg of a substance from solid state to liquid state, without a change in temperature Specific latent
heat of
vapourisation
HEAT ENERGY required to change 1 kg of a substance from liquid state to gaseous state, without a change in temperature
PRINCIPLE
Boyle’s Law Boyle’s Law states that 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)
Pressure Law The pressure law states that 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 Charles’ law states that 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
(C) Yeo Yih Tang 2009. Mail: [email protected] 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 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 snell’s law
Snell’s Law The value of sin i is a constant. sin r
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 Magnified image formed is larger than the object
(C) Yeo Yih Tang 2009. Mail: [email protected] Chapter 1 – Waves
Waves A TYPE OF DISTURBANCE produced by an oscillating or vibrating motion in which a 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 displacemen
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
(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, λ 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) a ↓ ; f =
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 = ; λ =
Refraction of wave Refraction of wave occurs when a wave travel from one medium to another f = ; v ≠ ; λ ≠ ; direction ≠
Diffraction of waves PHENOMENON in which waves spread out as they passed through an aperture or round a small circle
f = ; λ = ; 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.
(C) Yeo Yih Tang 2009. Mail: [email protected]
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 interacting waves at a point is the sum of the displacements of all the components waves at that point.
(C) Yeo Yih Tang 2009. Mail: [email protected] 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 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
Ohm’s Law Ohm’s 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, ܸ ן ܫ
(C) Yeo Yih Tang 2009. Mail: [email protected] Chapter 3 – Electromagnetism
Electromagnet DEVICE in which magnetism is produced by an electric current
TEMPORARY MAGNET which acts as a magnet when the current is switched on and ceases to be a magnet when the current is switched off
Magnetic field REGION in which a magnetic material experiences a force as the result of a magnet or a current-carrying conductor
Radial field MAGNETIC FIELD with the field lines pointing towards or away from the centre of a circle. Electromagnetic
induction PRODUCTION of an electric current by a changing magnetic field (conductor cuts across a magnetic flux –OR– a change of magnetic flux linkage with a coil) Root mean square
current/ voltage VALUE of a steady current/ voltage, which would produce the same heating effect in a given resistor. Transformer EQUIPMENT to raise or lower the potential difference of an alternating current supply PRINCIPLE
Faraday’s Law The magnitude of the induced electromotive force (e.m.f.) is directly proportional to the rate of change of magnetic flux linkage with the solenoid or the rate at which a conductor cuts through the magnetic flux.
Lenz’s Law Lenz’s law states that an induced electric current always flows in such a direction so as to oppose the change (or motion) producing it.
(C) Yeo Yih Tang 2009. Mail: [email protected] 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
Semiconductor Insulator
MATERIAL which allows current to flow thorugh them
MATERIAL whose resistance is between good conductor and 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 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
(C) Yeo Yih Tang 2009. Mail: [email protected] 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
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
Einstein’s Principle of
Mass-Energy Conservation The change of energy is linked to the change of mass by the equation ܧ ൌ ݉ܿ ଶ
