I must admit something bad, but I've been procrastinating.
This blog hasn't been updated in quite a few weeks, isn't it? This is because
I decided to dedicate my first post after my A' level examinations to my beloved late grandmother.
She died the day before my H2 Chemistry paper 1. I always felt that I was her favorite grandson, brought up by her youngest daughter. Her hope was that she could see me graduate from University.
But as I confessed, I've been doing some P. Thinking through what to write, and basically putting off the actually typing till now as it is something that is close to my heart. It's not only an opinion involved, but a life that involves me and my family.
Her life was one that glorified God. I realised that I do qualify to be a 3rd generation Christian as my grandmother was one of the first believers in China to accept Christ. There are not many ethnic Chinese here that can live up to that today.
Not only that, through her life as a living testimony, she managed her family well and brought her sons and daughters to also know Him, and subsequently to my generation as well.
Some of her stories:
- She was the 1st generation Singaporean, who migrated with her husband From China to Singapore to start a new life from the oppressive communist Middle Country.
- She gave birth to twelve kids, of which only six survived to reach adulthood.
- After one died by drowning, and she ordered that the older brothers teach all the children on how to swim. (I still remember my first experience of being dragged and thrown into the sea when I was young by my uncle such that I may learn how to swim in the choppy currents.)
- She gritted through WW2 as a lone woman when her husband was captured by the Japanese militants who underwent water torture; where the stomach is repeatedly pumped and expelled with huge amounts water, coupled with numerous beatings in between, to get information on spies. She even was pregnant at that time, and somehow managed to hold the baby through all the way after the Japanese surrender.
- At her village in the early days, she was known as the kind and virtuous woman who would not only carry water from a far local water source over many kilometres for her family, but for other families that could not do so for themselves too.
- Some people regarded her kindly and being superstitous, believed that my grandmother would be lucky enough to give birth to twins. Amazingly, that was the case - my mother was brought into this world as a boy-girl pair... as the two youngest children in her family.
Recounting these stories are only snippets of her life by her children that really affected the way my family runs and inspired other people to have God-centric lifes. One of the pastors that came for the bereavement commented that her life has inspired him to throw himself more fervorly into God's work. I am glad for him for honouring my grandma like that.
She could still do her own shopping for groceries earlier this year, until the time when her body suddenly detoriated until the point she was stick-thin and beddridden. There were quite a few times when she had to stay in the hospital, and I emphatise that she was unhappy about that, although everyone visited her more frequently. In the end, she died on a hospital bed.
And I didn't even say "Ah Ma, I love you" one last time...
Nevertheless, this song fits how my grandmother has affected me ever since I was a youngling. You Raise Me Up, by Josh Groban and African Children's Choir
She was a truly beautiful woman.
Ah Ma, if you're reading this, I love you, and thank you for watching over your family in heaven. Amen.
Friday, November 30, 2007
Sunday, November 11, 2007
11112007
First, HAPPY BIRTHDAY to tingx and zhanny!
a special 1111 to the now offical mature 18 peeps!
tingx -> dun pout, it's your bdae! Lotsa people will still celebrate with you real soon !!! Gambatte for the A's last few papers, and persevere!
zhanny -> maybe you dun know this, but i'm due to enlist on the SAME DAY as you. LOL. Thanks for making last year so memorable :) See you scoring A's everywhere, smart guy!
Second, for ALL Physics students taking A level 2mrw - a summary list! That's if you can read this in time (heez) for a quick revision.
Glossary : Definition List, by alphabet
Absorption line spectrum the spectrum produced when light from a hot body passes through a cooler gas; it appears as a series of separate dark lines on a continuous spectrum
Acceleration the rate of change of velocity of a body
Accuracy the extent to which a reading is close to the true value.
Accuracy the extent to which a reading is close to the true value.
Activity
the number of nuclear disintegrations per unit time. (Unit - Becquerel, Bq).
Amount of Substance the ratio of the number of discrete particles (atoms or molecules) of a substance to the number of atoms in 12g of carbon-12.
Amplitude is the maximum (magnitude of) displacement of any particle from its equilibrium position
Amplitude
maximum (magnitude of) displacement of the oscillating mass from its equilibrium position.
Angular velocity the rate of change in the angular displacement
Archimedes¡¯ Principle
states that when an object is totally or partially immersed in a fluid, it experiences an upward force (upthrust) equal to the weight of fluid displaced.
Atomic Number/Proton Number
the number of protons in the nucleus of an atom.
Avogadro constant is numerically equal to the number of atoms in 12g of carbon-12.
Avogadro Constant is numerically equal to the number of atoms in 12g of carbon- 12.
Background Radiation
the radiation detected by a radiation counter when no radioactive source is nearby.
Bandwidth the range of frequencies for which the gain is constant.
Base quantities & units l/m, m/kg, t/s, I/A, T/K, n/mol, luminous intensity, I/cd.
Bernoulli Effect
concerns pressure in a flowing fluid where the pressure decreases with increasing flow speeds.
Binding Energy
the energy released when a nucleus is formed from its constituent protons and neutrons.
Brownian motion
shows that fluids are composed of a large number of molecules in a state of continuous rapid random motion.
Brownian Motion shows that fluids are composed of a large number of molecules in a state of continuous rapid random motion.
Capacitance
the ratio of the charge Q that the capacitor stores to the potential difference V across the capacitor. (A measure of the charge storing ability of a capacitor)
Celsius scale of temperature is merely an arithmetical adjustment to the thermodynamic scale measured in Kelvin and is defined as q/ 0C = T / K ¨C 273.15.
Celsius scale of temperature is merely an arithmetical adjustment to the thermodynamic scale measured in Kelvin and is defined as q/ 0C = T / K – 273.15.
Centigrade scale of temperature one that has been established from experiment using the melting point of ice (0 0C) and steam (100 0C) as fixed points with 100 equal divisions.
Centigrade scale of temperature one that has been established from experiment using the melting point of ice (0 0C) and steam (100 0C) as fixed points with 100 equal divisions.
Centre of buoyancy
the centre of mass of the displaced fluid.
Centre of Gravity
the point through which the weight of the object appears to act.
Centre of gravity
the center of gravity of a body is a single point where the body¡¯s weight may be taken to act.
Centripetal force
is the radially inward resultant force that causes a body to move in a uniform circular motion.
Coherent sources waves of the same frequency with a constant phase difference
Compression/Rarefaction
a region in a medium where the pressure is above/below average
Conservation of Energy
the total energy for an isolated system remains constant.
Coulomb¡¯s law
the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
Critical Damping
the displacement is reduced to zero in the minimum time possible without any oscillations occurring.
Damped Oscillations oscillations in which the amplitude diminishes with time as a result of dissipative forces that reduce the total energy of the oscillations
Decay Constant
the probability of the decay of an atomic nucleus per unit time.
Density the mass of a substance per unit volume.
Diffraction
the spreading of waves around an obstacle or through a slit so that the waves do not travel in straight lines.
Diode
an electrical device that allows current through it in one direction only.
Displacement
the linear distance of the oscillating body from its equilibrium position at any instant in a specified direction.
Displacement
the distance of an object or a point, in a specified direction, from some reference point.
Distance the length of the path actually travelled by a body.
Efficiency ratio of the useful work got out of a machine to the energy put in.
Elastic collisions
between two bodies are collisions where the kinetic energy of the system is conserved. (Here, the relative speed of approach is equal to the relative speed of separation.)
Electric Charge
for a constant electric current I in a circuit, the electric charge DQ passing one point in the circuit in an interval of time Dt is given by DQ = IDt. (Note: Remember that the base quantity is electric current and the charge is defined in terms of current).
Coulomb ¨C it is the charge flowing per second past a point in a circuit in which the current is 1 ampere.
Electric Current a flow of charged particles
Electric Field a region where an electric charge experiences a force.
Electric Field strength the electric force per unit positive charge placed at the point.
Electric potential the work done per unit positive charge moving from infinity to the point.
Electromagnetic Induction the setting up, or inducing, of an electromotive force (emf) in a conductor whenever there is a change of magnetic flux linkage.
Electromotive force (emf)
the electrical energy generated per unit charge from some form of energy.
Emission line Spectrum
a series of separate, differently coloured lines on a black background corresponding to the wavelengths of electromagnetic radiation emitted by atoms when excited electrons in the atoms return to their ground states.
Empirical scale of temperature
one that has been established from experiment. (E.g. the Centigrade scale.)
Empirical scale of temperature one that has been established from experiment. (E.g. the Centigrade scale.)
Energy
is the capacity to do work.
Equilibrium position position at which no net force acts on the oscillation mass.
Excitation energy
energy required to rise from the ground to any of its higher energy levels.
Farad
it is defined as coulomb per unit volt.
Faraday¡¯s Law the magnitude of the induced emf in a coil is directly proportional to the rate of change of the magnetic flux linking (or cutting) the coil.
Feedback
process of taking some of the output of an amplifier and adding it to the input.
Field a region of space that can be mapped with lines of force or with lines of potential.
First Law of thermodynamics the increase in internal energy of a system is equal to the heat absorbed by the system, plus the work done on the system.
Force can be defined as the rate of change of momentum
Forced Oscillations
oscillations which results from the application of an external periodic force.
Free Oscillation
oscillations which occur at the natural frequency of a body when displaced from the equilibrium position and allowed to oscillate freely without the application of any external periodic force. (Note: In real life situations, damping forces will reduce the amplitude of the free oscillation).
Frequency the number of complete oscillations or cycles per unit time.
Frequency the number of revolutions per unit time
Frequency
the number of oscillations made per unit time.
Gain
ratio of the output voltage to its input voltage.
Geostationary Satellite one which is above the same spot above the Earth at all times
Gravitational Field a region of space where a mass experiences a force.
Gravitational Field Strength
the force per unit mass acting on a small mass placed at a point in the gravitational field.
Gravitational Potential
the work done per unit mass in bringing a point mass from infinity to that point.
Half-life the time taken for half the radioactive nuclei in a sample of the nuclide to decay.
Heat capacity
the quantity of heat needed to produce unit rise of temperature in the body.
Hooke¡¯s law
the force applied to any solid is proportional to the extension it produces within the proportionality limit for that solid.
Ideal fluid
a fluid which is incompressible (density of fluid remains constant) and non- viscous (internal friction is neglected, experience no retarding force).
Ideal Gas
one for which pV = nRT holds for all pressures and temperatures. (A real gas behaves ideally at very low pressures).
Ideal Gas one for which pV = nRT holds for all pressures and temperatures. (A real gas behaves ideally at very low pressures.)
Impulse (of a force)
the product of the force acting on an object and the time for which the force acts. (Note: The impulse is equal to the change in momentum of the given object).
Instantaneous speed
the speed at a particular point in time.
Instantaneous velocity
the average velocity for a diminishing time interval.
Intensity
the intensity of a wave is the wave energy incident per unit time per unit area normal to the wave.
Interference
an effect that occurs when two or more waves overlap (causing a change in amplitude) to produce a new wave pattern.
Internal energy (of a system)
is the sum of the random distribution of kinetic and potential energies associated with the particles that make up the system.
Internal energy (of a system) is the sum of the random distribution of kinetic and potential energies associated with the particles that make up the system.
Internal Resistance
the resistance to movement of charge within an electrical power source.
Ionization energy
energy that must be absorbed to remove an electron from an atom.
Isotope one of two or more atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons.
Kinetic energy the energy a body has because of its motion
Kinetic Theory of Gases
the basic assumptions:
¡¤ Gases consist of a very large number of atoms/molecules in continuous random motion.
¡¤ All collisions are perfectly elastic.
¡¤ The duration of collision is negligible compared with time interval between collisions.
¡¤ Intermolecular forces are negligible except during a collision.
¡¤ The volume of the all the gas molecules themselves are negligible compared with the volume occupied by the gas. (That is, the gas consists of mostly empty space).
Kinetic Theory of Gases - the 4 basic assumptions: · All collisions are perfectly elastic. · The duration of collision is negligible compared with time interval between collisions. · Intermolecular forces are negligible except during a collision. · The volume of the all the gas molecules themselves are negligible compared with the volume occupied by the gas. (That is, the gas consists of mostly empty space.)
Kirchhoff¡¯s First/Current/Junction Law
at any junction (or point) in a circuit, the total current entering the junction is equal to the total current leaving the junction. (Conservation of charge)
Kirchhoff¡¯s Second/Voltage/Loop Law
in any closed loop of a circuit, the total voltage drop is equal to the total voltage rise. (Conservation of Energy)
Lenz¡¯s law
the direction of the induced emf is always such that it produces effects to oppose the change causing it. (Principle of energy conservation)
Linear Momentum is the product of its mass and velocity.
Longitudinal wave
a wave in which the displacements of the particles in the wave are along the direction of the transfer of energy of the wave.
lst Law of thermodynamics
the increase in internal energy of a system is equal to the heat absorbed by the system, plus the work done on the system.
Magnetic field the region of space where a magnet, a current-carrying conductor or a moving charged particle will experience a force
Magnetic Flux
the product of the magnetic flux density and the area normal to the field through which the field is passing.
Magnetic Flux Density, B, of a magnetic field at a point
the force per unit length that acts on a wire carrying unit current lying at right angles to the magnetic field. (B= F/IL)
Tesla, T - the flux density of a uniform magnetic field when the force on a conductor 1m long, placed perpendicular to the field and carrying current of 1A, is 1N.
Magnetic Flux Linkage
the product, in a coil, of the magnetic flux passing through the coil and the number of turns on the coil.
Mass
it is a measure of a body¡¯s resistance to change in velocity. (Note: Do not confuse mass with amount of substance. The latter quantity is measured in moles).
Mass defect the difference between the total rest mass of the nucleons in a nucleus in the unbounded state and the rest mass of the nucleus
Mass Number/Nucleon Number
the number of nucleons (that is, protons and neutrons) found in the nucleus of a particular nuclide.
Metacentre
the point of intersection of the centre-line of the ship and the vertical line from the centre of buoyancy when it tips.
Mole unit of measurement of amount of substance. One mole of any substance contains a number of molecules (or atoms) equal to the Avogadro constant
Mole The amount of substance which contains as many elementary units as there are atoms in 0.012kg of carbon-12
Moment of a force
the product of the force and the perpendicular distance from the pivot to the line of action of the force.
Newton¡¯s First law
a body remains in a state of rest or of uniform motion in a straight line unless a net force acts on it.
Newton¡¯s Law of Gravitation
the force of attraction between two particles is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Newton¡¯s Second law the rate of change of momentum of a body is proportional to the external net force acting on it and occurs in the direction of the force.
Newton¡¯s Third law
when a body A exerts a force on another body B, B exerts a force of the same magnitude on A but in the opposite direction.
Node (Antinode)
a point on a stationary wave where the amplitude of vibration is zero or a minimum (maximum).
Nuclear Fission
the splitting of a nucleus of high nucleon number into two smaller nuclei of approximately equal mass with the emission of neutrons and release of energy.
Nuclear Fusion the building up of a larger nucleus from two nuclei of low nucleon number, with the release of energy.
Nucleus the central core of an atom containing protons and neutrons
Nuclide
a particular species of nucleus that is specified by its proton number and neutron number.
Ohm it is defined as volt per unit ampere.
Ohm¡¯s Law
for a conductor at constant temperature, the current in the conductor is proportional to the potential difference across it.
Path Difference the extra distance that one wave travels compared with another wave.
Period the time taken for the object to complete one revolution
Period the time required to complete one oscillation or cycle of motion.
Phase
an angle which gives a measure of the fraction of a cycle that has been completed by an oscillating particle or a wave.
Phase Difference
a measure of how much one wave is out of step with another.
Photoelectric Effect the ejection of an electron from a metal surface when the surface is irradiated with electromagnetic radiation of a high enough frequency.
Photon
a quantum of electromagnetic energy where each ¡®packet¡¯ of energy is proportional to the frequency of the radiation.
Plane Polarisation
where the oscillations in a wave are confined to one direction only, the direction being at right angles to the direction of propagation of the wave.
Potential difference the energy per unit charge dissipated from electrical energy to some other form when charge passes through an electrical component.
Potential energy
the energy possessed by a system by virtue of the relative positions of its component parts.
Power
the work done per unit time. (Or more generally, the rate of transfer of energy.)
Precision refers to the narrowness of spread of a set of readings. (It is also a term used to describe the extent or limit of sensitivity of an instrument).
Precision refers to the narrowness of spread of a set of readings.
Pressure the force exerted normally per unit area
Principle of Conservation of Momentum
states that the total momentum of an isolated system of bodies is constant. (Or the total momentum of a system is constant provided no external net force acts on the system.)
Principle of Flotation
a floating object in a fluid displaces a weight of fluid equal to its own weight.
Principle of Superposition
states that when two or more waves meet at a point, the resultant displacement at that point is the vector sum of the individual displacements.
Progressive/Travelling wave
a wave whereby energy is transferred from one point to another by means of vibrations or oscillations within the wave.
Radioactivity
is the spontaneous nuclear disintegration in which an unstable nucleus with the emission of one or two of the different types of radiation namely alpha, beta and gamma.
Random error results in a scatter of readings about a mean value. They have an equal chance of being negative or positive.
Random error results in a scatter of readings about a mean value with an equal chance of the error being negative or positive.
Randomness
this describes the nature of radioactive decay (shown by the fluctuation of the decay readings for any given sample of a radioactive material, it is not possible to predict which nucleus will decay next and exact when it would decay. (Note: Although the decays in a sample may be random, any nucleus has a constant probability of decay per unit time, referred to as the decay constant).
Rectification the means by which alternating current is converted into direct current
Resistance the ratio of the potential difference across an electrical component to the current passing through it.
Resistance vs Thermocouple Thermometers compare relative advantages/disadvantages
Resistivity
is numerically equal to the resistance of a sample of unit length and unit cross-sectional area at a particular constant temperature.
Resonance
a phenomenon that occurs when the frequency at which an object is being made to vibrate (the driving frequency) is equal to its natural frequency which causes it to vibrate at a maximum amplitude.
Root-Mean-Square value (r.m.s) of an a.c the equivalent value of the steady d.c. which would dissipate heat at the same average rate as the a.c. in a given load.
Satellite a body in space orbiting around a much larger one
Scalar a physical quantity that has only a magnitude and unit.
Scalar a physical quantity that has only a magnitude and unit
Simple Harmonic Motion the motion of a body for which its acceleration is directly proportional to its displacement from a fixed point and is always directed towards that point.
Specific charge the ratio of the charge on a particle to its mass
Specific heat capacity the quantity of heat required to produce unit rise of temperature per unit mass of the substance.
Specific heat capacity
the quantity of heat required to produce unit rise of temperature per unit mass of the substance.
Specific latent heat of fusion
the quantity of heat required to change unit mass of a substance from solid to liquid without a change of temperature.
Specific latent heat of fusion the quantity of heat required to change unit mass of a substance from solid to liquid without a change of temperature.
Specific latent heat of vaporization the quantity of heat required to change unit mass of a substance from liquid to vapour without a change of temperature.
Specific latent heat of vaporization
the quantity of heat required to change unit mass of a substance from liquid to vapour without a change of temperature.
Speed the time rate of the total distance travelled
Spontaneous Decay
the emission is unaffected by environmental factors such as temperature and pressure.
Stability a body¡¯s resistance to subsequent motion after an initial disturbance
Standing/Stationary Wave a wave in which vibrational energy is stored, rather than transmitted as in a progressive wave. A stationary wave is the result of two progressive waves, of the same frequency, traveling in opposite directions along the same line. If the phase difference between the two waves is correct, a stationary wave is formed
Stokes¡¯ law a law that states that the viscous (drag) force opposing the streamline flow of a sphere is directly proportional to the speed of the sphere relative to the fluid
Stopping Potential
the minimum retarding voltage for which no photoelectrons reach the anode. (That is, current reading is zero).
Streamline/Laminar Flow
the smooth steady flow of a fluid without any disturbances such as eddies.
System in equilibrium
when there is no resultant force and no resultant torque (moment) on the system.
Systematic error results in all the readings taken being faulty in one direction.
Systematic error It is a constant deviation of the readings, which yields a consistent over-estimation or underestimation from the true value.
Temperature the measure of a body’s degree of hotness and coldness. (A common property of 2 bodies that are in thermal equilibrium. Microscopically, the measure of the mean translational kinetic energy of the molecules of an ideal gas.)
Temperature
the measure of a body¡¯s degree of hotness and coldness. (A common property of 2 bodies that are in thermal equilibrium. Microscopically, the measure of the mean translational kinetic energy of the molecules of an ideal gas.)
Terminal Velocity
the constant velocity achieved by an object when it is falling under gravity through a viscous fluid.
Thermal equilibrium two bodies are said to be in thermal equilibrium if there is no net heat flow between them; that is, they have the same temperature.
Thermal equilibrium two bodies are said to be in thermal equilibrium if there is no net heat flow between them; that is, they have the same temperature.
Thermodynamic scale of temperature
an absolute scale of temperature which is based on theory and does not depend on the property of any particular substance. (E.g. the Kelvin scale.)
Thermodynamic scale of temperature an absolute scale of temperature which is based on theory and does not depend on the property of any particular substance. (E.g. the Kelvin scale.)
Thermometric property a physical property that varies continuously with temperature.
Thermometric property
a physical property that varies continuously with temperature.
Threshold frequency the minimum frequency of electromagnetic radiation below which no photoelectric emission is possible
Torque of a couple
the product of one of the forces and the perpendicular distance separating the forces. It tends to produce rotation only.
Transformer a device by which the voltage of an alternating supply may be changed
Transverse wave a wave in which the displacements of the particles in the wave are at right angles to the direction of the transfer of energy of the wave
Triple point of water
the temperature at which all the three states of water co-exist in equilibrium. (273.16 K)
Triple point of water the temperature at which all the three states of water co-exist in equilibrium. (273.16 K)
Turbulent Flow the type of flow that occurs when the speed of a fluid is sufficiently high for streamline flow not to occur; it is characterized by irregular paths and eddies
Unified Atomic Mass Unit the mass of one-twelfth of the mass of a carbon-12 atom.
Upthrust
the upward push exerted on an object due to the displacement of fluid in which the object is submerged.
Vector
a physical quantity that has both direction and magnitude, and a unit.
Velocity the rate of change of displacement with time of a body
Viscosity
the frictional forces acting between neighbouring layers of fluid when they are moving over each other at different speeds.
Volt
it is defined as joule per coulomb (or watt per ampere).
Wave motion is the transfer of energy between 2 points without the actual transfer of the material medium between the 2 points.
Wave speed distance travelled by the wave in unit time. (speed of propagation)
Wavelength
the shortest distance between two points on a progressive wave which are vibrating in phase.
Weight
a force acting on a body due to gravity.
Work is the product of the force and the distance moved in the direction of the force
Work function energy
the minimum energy required to eject an electron from the surface of a metal in the photoelectric effect.
[END]
That's it. Tata~!
a special 1111 to the now offical mature 18 peeps!
tingx -> dun pout, it's your bdae! Lotsa people will still celebrate with you real soon !!! Gambatte for the A's last few papers, and persevere!
zhanny -> maybe you dun know this, but i'm due to enlist on the SAME DAY as you. LOL. Thanks for making last year so memorable :) See you scoring A's everywhere, smart guy!
Second, for ALL Physics students taking A level 2mrw - a summary list! That's if you can read this in time (heez) for a quick revision.
Glossary : Definition List, by alphabet
Absorption line spectrum the spectrum produced when light from a hot body passes through a cooler gas; it appears as a series of separate dark lines on a continuous spectrum
Acceleration the rate of change of velocity of a body
Accuracy the extent to which a reading is close to the true value.
Accuracy the extent to which a reading is close to the true value.
Activity
the number of nuclear disintegrations per unit time. (Unit - Becquerel, Bq).
Amount of Substance the ratio of the number of discrete particles (atoms or molecules) of a substance to the number of atoms in 12g of carbon-12.
Amplitude is the maximum (magnitude of) displacement of any particle from its equilibrium position
Amplitude
maximum (magnitude of) displacement of the oscillating mass from its equilibrium position.
Angular velocity the rate of change in the angular displacement
Archimedes¡¯ Principle
states that when an object is totally or partially immersed in a fluid, it experiences an upward force (upthrust) equal to the weight of fluid displaced.
Atomic Number/Proton Number
the number of protons in the nucleus of an atom.
Avogadro constant is numerically equal to the number of atoms in 12g of carbon-12.
Avogadro Constant is numerically equal to the number of atoms in 12g of carbon- 12.
Background Radiation
the radiation detected by a radiation counter when no radioactive source is nearby.
Bandwidth the range of frequencies for which the gain is constant.
Base quantities & units l/m, m/kg, t/s, I/A, T/K, n/mol, luminous intensity, I/cd.
Bernoulli Effect
concerns pressure in a flowing fluid where the pressure decreases with increasing flow speeds.
Binding Energy
the energy released when a nucleus is formed from its constituent protons and neutrons.
Brownian motion
shows that fluids are composed of a large number of molecules in a state of continuous rapid random motion.
Brownian Motion shows that fluids are composed of a large number of molecules in a state of continuous rapid random motion.
Capacitance
the ratio of the charge Q that the capacitor stores to the potential difference V across the capacitor. (A measure of the charge storing ability of a capacitor)
Celsius scale of temperature is merely an arithmetical adjustment to the thermodynamic scale measured in Kelvin and is defined as q/ 0C = T / K ¨C 273.15.
Celsius scale of temperature is merely an arithmetical adjustment to the thermodynamic scale measured in Kelvin and is defined as q/ 0C = T / K – 273.15.
Centigrade scale of temperature one that has been established from experiment using the melting point of ice (0 0C) and steam (100 0C) as fixed points with 100 equal divisions.
Centigrade scale of temperature one that has been established from experiment using the melting point of ice (0 0C) and steam (100 0C) as fixed points with 100 equal divisions.
Centre of buoyancy
the centre of mass of the displaced fluid.
Centre of Gravity
the point through which the weight of the object appears to act.
Centre of gravity
the center of gravity of a body is a single point where the body¡¯s weight may be taken to act.
Centripetal force
is the radially inward resultant force that causes a body to move in a uniform circular motion.
Coherent sources waves of the same frequency with a constant phase difference
Compression/Rarefaction
a region in a medium where the pressure is above/below average
Conservation of Energy
the total energy for an isolated system remains constant.
Coulomb¡¯s law
the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
Critical Damping
the displacement is reduced to zero in the minimum time possible without any oscillations occurring.
Damped Oscillations oscillations in which the amplitude diminishes with time as a result of dissipative forces that reduce the total energy of the oscillations
Decay Constant
the probability of the decay of an atomic nucleus per unit time.
Density the mass of a substance per unit volume.
Diffraction
the spreading of waves around an obstacle or through a slit so that the waves do not travel in straight lines.
Diode
an electrical device that allows current through it in one direction only.
Displacement
the linear distance of the oscillating body from its equilibrium position at any instant in a specified direction.
Displacement
the distance of an object or a point, in a specified direction, from some reference point.
Distance the length of the path actually travelled by a body.
Efficiency ratio of the useful work got out of a machine to the energy put in.
Elastic collisions
between two bodies are collisions where the kinetic energy of the system is conserved. (Here, the relative speed of approach is equal to the relative speed of separation.)
Electric Charge
for a constant electric current I in a circuit, the electric charge DQ passing one point in the circuit in an interval of time Dt is given by DQ = IDt. (Note: Remember that the base quantity is electric current and the charge is defined in terms of current).
Coulomb ¨C it is the charge flowing per second past a point in a circuit in which the current is 1 ampere.
Electric Current a flow of charged particles
Electric Field a region where an electric charge experiences a force.
Electric Field strength the electric force per unit positive charge placed at the point.
Electric potential the work done per unit positive charge moving from infinity to the point.
Electromagnetic Induction the setting up, or inducing, of an electromotive force (emf) in a conductor whenever there is a change of magnetic flux linkage.
Electromotive force (emf)
the electrical energy generated per unit charge from some form of energy.
Emission line Spectrum
a series of separate, differently coloured lines on a black background corresponding to the wavelengths of electromagnetic radiation emitted by atoms when excited electrons in the atoms return to their ground states.
Empirical scale of temperature
one that has been established from experiment. (E.g. the Centigrade scale.)
Empirical scale of temperature one that has been established from experiment. (E.g. the Centigrade scale.)
Energy
is the capacity to do work.
Equilibrium position position at which no net force acts on the oscillation mass.
Excitation energy
energy required to rise from the ground to any of its higher energy levels.
Farad
it is defined as coulomb per unit volt.
Faraday¡¯s Law the magnitude of the induced emf in a coil is directly proportional to the rate of change of the magnetic flux linking (or cutting) the coil.
Feedback
process of taking some of the output of an amplifier and adding it to the input.
Field a region of space that can be mapped with lines of force or with lines of potential.
First Law of thermodynamics the increase in internal energy of a system is equal to the heat absorbed by the system, plus the work done on the system.
Force can be defined as the rate of change of momentum
Forced Oscillations
oscillations which results from the application of an external periodic force.
Free Oscillation
oscillations which occur at the natural frequency of a body when displaced from the equilibrium position and allowed to oscillate freely without the application of any external periodic force. (Note: In real life situations, damping forces will reduce the amplitude of the free oscillation).
Frequency the number of complete oscillations or cycles per unit time.
Frequency the number of revolutions per unit time
Frequency
the number of oscillations made per unit time.
Gain
ratio of the output voltage to its input voltage.
Geostationary Satellite one which is above the same spot above the Earth at all times
Gravitational Field a region of space where a mass experiences a force.
Gravitational Field Strength
the force per unit mass acting on a small mass placed at a point in the gravitational field.
Gravitational Potential
the work done per unit mass in bringing a point mass from infinity to that point.
Half-life the time taken for half the radioactive nuclei in a sample of the nuclide to decay.
Heat capacity
the quantity of heat needed to produce unit rise of temperature in the body.
Hooke¡¯s law
the force applied to any solid is proportional to the extension it produces within the proportionality limit for that solid.
Ideal fluid
a fluid which is incompressible (density of fluid remains constant) and non- viscous (internal friction is neglected, experience no retarding force).
Ideal Gas
one for which pV = nRT holds for all pressures and temperatures. (A real gas behaves ideally at very low pressures).
Ideal Gas one for which pV = nRT holds for all pressures and temperatures. (A real gas behaves ideally at very low pressures.)
Impulse (of a force)
the product of the force acting on an object and the time for which the force acts. (Note: The impulse is equal to the change in momentum of the given object).
Instantaneous speed
the speed at a particular point in time.
Instantaneous velocity
the average velocity for a diminishing time interval.
Intensity
the intensity of a wave is the wave energy incident per unit time per unit area normal to the wave.
Interference
an effect that occurs when two or more waves overlap (causing a change in amplitude) to produce a new wave pattern.
Internal energy (of a system)
is the sum of the random distribution of kinetic and potential energies associated with the particles that make up the system.
Internal energy (of a system) is the sum of the random distribution of kinetic and potential energies associated with the particles that make up the system.
Internal Resistance
the resistance to movement of charge within an electrical power source.
Ionization energy
energy that must be absorbed to remove an electron from an atom.
Isotope one of two or more atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons.
Kinetic energy the energy a body has because of its motion
Kinetic Theory of Gases
the basic assumptions:
¡¤ Gases consist of a very large number of atoms/molecules in continuous random motion.
¡¤ All collisions are perfectly elastic.
¡¤ The duration of collision is negligible compared with time interval between collisions.
¡¤ Intermolecular forces are negligible except during a collision.
¡¤ The volume of the all the gas molecules themselves are negligible compared with the volume occupied by the gas. (That is, the gas consists of mostly empty space).
Kinetic Theory of Gases - the 4 basic assumptions: · All collisions are perfectly elastic. · The duration of collision is negligible compared with time interval between collisions. · Intermolecular forces are negligible except during a collision. · The volume of the all the gas molecules themselves are negligible compared with the volume occupied by the gas. (That is, the gas consists of mostly empty space.)
Kirchhoff¡¯s First/Current/Junction Law
at any junction (or point) in a circuit, the total current entering the junction is equal to the total current leaving the junction. (Conservation of charge)
Kirchhoff¡¯s Second/Voltage/Loop Law
in any closed loop of a circuit, the total voltage drop is equal to the total voltage rise. (Conservation of Energy)
Lenz¡¯s law
the direction of the induced emf is always such that it produces effects to oppose the change causing it. (Principle of energy conservation)
Linear Momentum is the product of its mass and velocity.
Longitudinal wave
a wave in which the displacements of the particles in the wave are along the direction of the transfer of energy of the wave.
lst Law of thermodynamics
the increase in internal energy of a system is equal to the heat absorbed by the system, plus the work done on the system.
Magnetic field the region of space where a magnet, a current-carrying conductor or a moving charged particle will experience a force
Magnetic Flux
the product of the magnetic flux density and the area normal to the field through which the field is passing.
Magnetic Flux Density, B, of a magnetic field at a point
the force per unit length that acts on a wire carrying unit current lying at right angles to the magnetic field. (B= F/IL)
Tesla, T - the flux density of a uniform magnetic field when the force on a conductor 1m long, placed perpendicular to the field and carrying current of 1A, is 1N.
Magnetic Flux Linkage
the product, in a coil, of the magnetic flux passing through the coil and the number of turns on the coil.
Mass
it is a measure of a body¡¯s resistance to change in velocity. (Note: Do not confuse mass with amount of substance. The latter quantity is measured in moles).
Mass defect the difference between the total rest mass of the nucleons in a nucleus in the unbounded state and the rest mass of the nucleus
Mass Number/Nucleon Number
the number of nucleons (that is, protons and neutrons) found in the nucleus of a particular nuclide.
Metacentre
the point of intersection of the centre-line of the ship and the vertical line from the centre of buoyancy when it tips.
Mole unit of measurement of amount of substance. One mole of any substance contains a number of molecules (or atoms) equal to the Avogadro constant
Mole The amount of substance which contains as many elementary units as there are atoms in 0.012kg of carbon-12
Moment of a force
the product of the force and the perpendicular distance from the pivot to the line of action of the force.
Newton¡¯s First law
a body remains in a state of rest or of uniform motion in a straight line unless a net force acts on it.
Newton¡¯s Law of Gravitation
the force of attraction between two particles is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Newton¡¯s Second law the rate of change of momentum of a body is proportional to the external net force acting on it and occurs in the direction of the force.
Newton¡¯s Third law
when a body A exerts a force on another body B, B exerts a force of the same magnitude on A but in the opposite direction.
Node (Antinode)
a point on a stationary wave where the amplitude of vibration is zero or a minimum (maximum).
Nuclear Fission
the splitting of a nucleus of high nucleon number into two smaller nuclei of approximately equal mass with the emission of neutrons and release of energy.
Nuclear Fusion the building up of a larger nucleus from two nuclei of low nucleon number, with the release of energy.
Nucleus the central core of an atom containing protons and neutrons
Nuclide
a particular species of nucleus that is specified by its proton number and neutron number.
Ohm it is defined as volt per unit ampere.
Ohm¡¯s Law
for a conductor at constant temperature, the current in the conductor is proportional to the potential difference across it.
Path Difference the extra distance that one wave travels compared with another wave.
Period the time taken for the object to complete one revolution
Period the time required to complete one oscillation or cycle of motion.
Phase
an angle which gives a measure of the fraction of a cycle that has been completed by an oscillating particle or a wave.
Phase Difference
a measure of how much one wave is out of step with another.
Photoelectric Effect the ejection of an electron from a metal surface when the surface is irradiated with electromagnetic radiation of a high enough frequency.
Photon
a quantum of electromagnetic energy where each ¡®packet¡¯ of energy is proportional to the frequency of the radiation.
Plane Polarisation
where the oscillations in a wave are confined to one direction only, the direction being at right angles to the direction of propagation of the wave.
Potential difference the energy per unit charge dissipated from electrical energy to some other form when charge passes through an electrical component.
Potential energy
the energy possessed by a system by virtue of the relative positions of its component parts.
Power
the work done per unit time. (Or more generally, the rate of transfer of energy.)
Precision refers to the narrowness of spread of a set of readings. (It is also a term used to describe the extent or limit of sensitivity of an instrument).
Precision refers to the narrowness of spread of a set of readings.
Pressure the force exerted normally per unit area
Principle of Conservation of Momentum
states that the total momentum of an isolated system of bodies is constant. (Or the total momentum of a system is constant provided no external net force acts on the system.)
Principle of Flotation
a floating object in a fluid displaces a weight of fluid equal to its own weight.
Principle of Superposition
states that when two or more waves meet at a point, the resultant displacement at that point is the vector sum of the individual displacements.
Progressive/Travelling wave
a wave whereby energy is transferred from one point to another by means of vibrations or oscillations within the wave.
Radioactivity
is the spontaneous nuclear disintegration in which an unstable nucleus with the emission of one or two of the different types of radiation namely alpha, beta and gamma.
Random error results in a scatter of readings about a mean value. They have an equal chance of being negative or positive.
Random error results in a scatter of readings about a mean value with an equal chance of the error being negative or positive.
Randomness
this describes the nature of radioactive decay (shown by the fluctuation of the decay readings for any given sample of a radioactive material, it is not possible to predict which nucleus will decay next and exact when it would decay. (Note: Although the decays in a sample may be random, any nucleus has a constant probability of decay per unit time, referred to as the decay constant).
Rectification the means by which alternating current is converted into direct current
Resistance the ratio of the potential difference across an electrical component to the current passing through it.
Resistance vs Thermocouple Thermometers compare relative advantages/disadvantages
Resistivity
is numerically equal to the resistance of a sample of unit length and unit cross-sectional area at a particular constant temperature.
Resonance
a phenomenon that occurs when the frequency at which an object is being made to vibrate (the driving frequency) is equal to its natural frequency which causes it to vibrate at a maximum amplitude.
Root-Mean-Square value (r.m.s) of an a.c the equivalent value of the steady d.c. which would dissipate heat at the same average rate as the a.c. in a given load.
Satellite a body in space orbiting around a much larger one
Scalar a physical quantity that has only a magnitude and unit.
Scalar a physical quantity that has only a magnitude and unit
Simple Harmonic Motion the motion of a body for which its acceleration is directly proportional to its displacement from a fixed point and is always directed towards that point.
Specific charge the ratio of the charge on a particle to its mass
Specific heat capacity the quantity of heat required to produce unit rise of temperature per unit mass of the substance.
Specific heat capacity
the quantity of heat required to produce unit rise of temperature per unit mass of the substance.
Specific latent heat of fusion
the quantity of heat required to change unit mass of a substance from solid to liquid without a change of temperature.
Specific latent heat of fusion the quantity of heat required to change unit mass of a substance from solid to liquid without a change of temperature.
Specific latent heat of vaporization the quantity of heat required to change unit mass of a substance from liquid to vapour without a change of temperature.
Specific latent heat of vaporization
the quantity of heat required to change unit mass of a substance from liquid to vapour without a change of temperature.
Speed the time rate of the total distance travelled
Spontaneous Decay
the emission is unaffected by environmental factors such as temperature and pressure.
Stability a body¡¯s resistance to subsequent motion after an initial disturbance
Standing/Stationary Wave a wave in which vibrational energy is stored, rather than transmitted as in a progressive wave. A stationary wave is the result of two progressive waves, of the same frequency, traveling in opposite directions along the same line. If the phase difference between the two waves is correct, a stationary wave is formed
Stokes¡¯ law a law that states that the viscous (drag) force opposing the streamline flow of a sphere is directly proportional to the speed of the sphere relative to the fluid
Stopping Potential
the minimum retarding voltage for which no photoelectrons reach the anode. (That is, current reading is zero).
Streamline/Laminar Flow
the smooth steady flow of a fluid without any disturbances such as eddies.
System in equilibrium
when there is no resultant force and no resultant torque (moment) on the system.
Systematic error results in all the readings taken being faulty in one direction.
Systematic error It is a constant deviation of the readings, which yields a consistent over-estimation or underestimation from the true value.
Temperature the measure of a body’s degree of hotness and coldness. (A common property of 2 bodies that are in thermal equilibrium. Microscopically, the measure of the mean translational kinetic energy of the molecules of an ideal gas.)
Temperature
the measure of a body¡¯s degree of hotness and coldness. (A common property of 2 bodies that are in thermal equilibrium. Microscopically, the measure of the mean translational kinetic energy of the molecules of an ideal gas.)
Terminal Velocity
the constant velocity achieved by an object when it is falling under gravity through a viscous fluid.
Thermal equilibrium two bodies are said to be in thermal equilibrium if there is no net heat flow between them; that is, they have the same temperature.
Thermal equilibrium two bodies are said to be in thermal equilibrium if there is no net heat flow between them; that is, they have the same temperature.
Thermodynamic scale of temperature
an absolute scale of temperature which is based on theory and does not depend on the property of any particular substance. (E.g. the Kelvin scale.)
Thermodynamic scale of temperature an absolute scale of temperature which is based on theory and does not depend on the property of any particular substance. (E.g. the Kelvin scale.)
Thermometric property a physical property that varies continuously with temperature.
Thermometric property
a physical property that varies continuously with temperature.
Threshold frequency the minimum frequency of electromagnetic radiation below which no photoelectric emission is possible
Torque of a couple
the product of one of the forces and the perpendicular distance separating the forces. It tends to produce rotation only.
Transformer a device by which the voltage of an alternating supply may be changed
Transverse wave a wave in which the displacements of the particles in the wave are at right angles to the direction of the transfer of energy of the wave
Triple point of water
the temperature at which all the three states of water co-exist in equilibrium. (273.16 K)
Triple point of water the temperature at which all the three states of water co-exist in equilibrium. (273.16 K)
Turbulent Flow the type of flow that occurs when the speed of a fluid is sufficiently high for streamline flow not to occur; it is characterized by irregular paths and eddies
Unified Atomic Mass Unit the mass of one-twelfth of the mass of a carbon-12 atom.
Upthrust
the upward push exerted on an object due to the displacement of fluid in which the object is submerged.
Vector
a physical quantity that has both direction and magnitude, and a unit.
Velocity the rate of change of displacement with time of a body
Viscosity
the frictional forces acting between neighbouring layers of fluid when they are moving over each other at different speeds.
Volt
it is defined as joule per coulomb (or watt per ampere).
Wave motion is the transfer of energy between 2 points without the actual transfer of the material medium between the 2 points.
Wave speed distance travelled by the wave in unit time. (speed of propagation)
Wavelength
the shortest distance between two points on a progressive wave which are vibrating in phase.
Weight
a force acting on a body due to gravity.
Work is the product of the force and the distance moved in the direction of the force
Work function energy
the minimum energy required to eject an electron from the surface of a metal in the photoelectric effect.
[END]
That's it. Tata~!
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