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
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
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 decreased by any transformation. Energy cannot be created 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 law of motion
Newton’s third law of motion states that to every action there is an equal but opposite reaction.
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 principle
Bernoulli’s principle states that the pressure of a moving fluid decreases as the speed of the fluid increases, and the converse is also true.
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 (V/T = k)
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 Real Laterally inverted Upright Diminished Magnified
an image which cannot be projected (focused) onto a screen an image which can be projected (focused) onto a screen an image which left and right are interchanged an image which in vertical position image formed is smaller than the object image formed is larger than the object
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 system oscillates at its its natural frequency by an external force. The resonating system maximum amplitude.
Natural frequency
FUNDAMENTAL FUNDAMENTAL FREQUENCY of which an object vibrates. 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 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.
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.
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 co nductor to the current flowing through it MEASURE of the ability of the conductor to r esist 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,
Chapter 3 – Electromagnetism Electromagnet
DEVICE in which magnetism is produced by an elec tric current TEMPORARY 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 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 magnetic field (conductor cuts across a magnetic flux –OR– a change of magnetic flux linkage 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 electromoti e lectromotive ve 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.
Chapter 4 – Electronics Thermoionic emission
EMISSION of electrons from hot metal surface
Work function
MINIMUM ENERGY required to eject electrons from surface
Cathode ray
ELECTRONS travel in a straight line in vacuum fast moving ELECTRONS
Cathode ray oscilloscope
measuring and testing INSTRUMENT used in study of electricity and electronics
MATERIAL which allows current to flow thorugh them Conductor Semiconductor MATERIAL whose resistance is between good conductor and insulator MATERIAL which does not conduct electric current Insulator
Junction voltage
POTENTIAL DIFFERENCE 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
Logic gates
ELECTRONIC SWITCHES 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
Radioactive decay
PROCESS where an unstable nucleus becomes a more stable nuc leus 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 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
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