Physics Revision
Unit 8:- Energy Sources and Transfer of Energy (j) recall and use the formula for % Efficiency?
% Efficiency = Useful Energy or Power Output/ Total Energy or Power Input x 100%
Unit 8:- Energy Sources and Transfer of Energy (e) describe the processes by which energy is converted from one form to another, including reference to
(1) chemical/fuel energy (a re-grouping of atoms), >(Fuel)Chemical E.-->(Turbine)Thermal E.-->(Generator)Kinetic E.-->(Generator)Electrical E. (2) hydroelectric generation (emphasising the mechanical energies involved), >(Water)Grav. Ep-->(Turbine)Kinetic Energy-->(Generator)Electrical Energy. (3)Solar energy (nuclei of atoms in the Sun), >Solar Energy-->"Photovoltaic"-->Electrical Energy >(Steam)Thermal Energy-->(Turbine)Kinetic Energy-->(Generator)Electrical Energy (4) nuclear energy, >(Uranium)Nuclear Energy-->(Steam)Thermal Energy-->(Turbine)Kinetic Energy-->(Generator)Electrical Energy (5) geothermal energy >(Steam)Thermal Energy-->(Turbine)Kinetic Energy-->(Generator)Electrical Energy (6) wind energy. >(Air)Kinetic Energy-->(Turbine)Kinetic Energy-->(Generator)Electrical Energy.
Unit 15:- Electromagnetic Spectrum (d) describe the main components of the electromagnetic spectrum
(1) radio waves (2) microwaves (3) infra-red (4) light (5) ultra-violet (6) X-rays (7) gamma rays >Radio waves have the longest wavelength but are of low frequency waves. They carry very little energy >Gamma rays have the shortest wavelength but are of high frequency waves. They carry very high energy.
Unit 15:- Electromagnetic Spectrum (e) discuss the role of the following components in the stated applications: (1) radio waves (2) microwaves (3) infra-red (4) light (5) ultra-violet (6) X-rays (7) gamma rays
(1) radio waves - radio and television communications, (2) microwaves - satellite television and telephone, (3) infra-red - household electrical appliances, television controllers and intruder alarms, (4) light - optical fibres in medical uses and telephone, (5) ultra-violet - sunbeds, fluorescent tubes and sterilisation, (6) X-rays - hospital use in medical imaging and killing cancerous cells, and engineering applications such as detecting cracks in metal, (7) gamma rays - medical treatment in killing cancerous cells, and engineering applications such as detecting cracks in metal.
Unit 7:- Pressure (b) explain how pressure varies with force and area in the context of everyday examples
(1)P%F The Greater the force, the greater will be the pressure (2)p%1/A The smaller the area, the greater will be the pressure
Unit 1:- Physical Quantities, Units and Measurement (d) describe how to measure a variety of lengths with appropriate accuracy using tapes, rules, micrometers and calipers. (The use of a vernier scale is not required.)
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Unit 24:- Introductory Electronics (m) describe and explain circuits operating as light-sensitive switches and temperature-operated alarms (using a relay or other circuits).
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Unit 24:- Introductory Electronics (f) explain how the values of resistors are chosen according to a colour code and why widely different values are needed in different types of circuit.
-The resistor is a device used to control, the amount of current flowing through a conductor.
Unit 27:- The Nuclear Atom (b) describe how the Geiger-Marsden alpha-particle scattering experiment provides evidence for the nuclear atom.
1)A beam of alpha particles was aimed at a thin piece of gold foil 2)A Zinc sulfate screen mounted on a rotatable microscope was used to detect the alpha particles 3)Experiment was conducted in a darkened room-->so that very small flash of light would be seen whenever an alpha particles hits the Zinc Sulphide Screen 4)Most of the alpha particles passed straight through the gold foil, a very small fraction of the alpha particles bounced back towards the source >> Atom is mainly Empty Space, that why most of the alpha particles pass straight through the gold foil >Only a small number of the positively charged alpha particles are deviated by repulsion due to positively charged nucleus of the gold foil.
Unit 14:- Light (c) describe an experiment to find the position and characteristics of an optical image formed by a plane mirror.
1)Apparatus is set as shown 2)The image is formed is observed 3)The no. of squares between the pins and the mirror as well as between the images and the mirror are counted to find the distances d1 and d2 respectively. 4)The two distances are compared. CONCLUSIONS 1. laterally inverted, 2. same size as the object, 3. virtual 4. upright 5. as far behind the mirror as the object is in front of it. Notes: Real image : Image that can be seen on a screen Virtual image : Image that cannot be seen on a screen.
Unit 8:- Energy Sources and Transfer of Energy (h) discuss the environmental issues associated with power generation.
1)Burning of Coal and Oil Produce Gases such as Sulphur dioxide which are poisonous and form acid rain 2)Nuclear Fuels must be used carefully as it gives off harmful radiation which can cause cancer >Environmental Issues of Electricity Production. The variety of fuels used to generate electricity all have some impact on the environment. Fossil fuel power plants release air pollution, require large amounts of cooling water, and can mar large tracts of land during the mining process.
Unit 26:- Radioactivity (a) describe the detection of alpha-particles, beta-particles and gamma rays by appropriate methods.
1)Diffusion Cloud Chamber 2)Geiger Muller Tube 3)Gold Leaf Electroscope 4)Photography
Unit 11:- Thermal Properties of Matter (g3)State and define the two types of latent heat?
1)Latent heat of fusion(Lf) >It is the amount of energy required to change a substance from solid to liquid without a change in temperature 2)Latent heat of Vaporization(Lv) >It is the amount of energy required to change a substance from liquid to gas without a change in temperature
Unit 14:- Light (o) describe the use of a single lens as a magnifying glass and in a camera, projector and photographic enlarger and draw ray diagrams to show how each forms an image.
1)Magnifying Glass:- u<f >Inverted >Real >magnified 2)Camera:- u>2f >Inverted >Real >Diminished 3)Projector:- f < u <2f >Inverted >Real >Diminished 4)Photographic Enlarger:- f < u <2f >Inverted >Real >Magnified
Unit 17:-Magnetism and Electromagnetism (e) Describe the plotting of magnetic field using a magnet.
1)Place a bar Magnet at the center of a piece of paper 2)Draw a layout on the sheet of paper 3)Take the compass to the N-pole of magnet, the S-pole needle is attracted to the N-pole of the magnet 4)Mark the position of the N-pole of the needle with '1' 5)Move the compass untill the S-pole of the needle resizes exactly with dot '1' 6)Mark new position of the N-pole with another dot. 7) Repeat Step 5 until S-pole of the magnet is reached. 8)Join the dots to obtain the magnetic lines of force 9)Repeat above procedures to plot other magnetic lines of force.
Unit 11:- Thermal Properties of Matter (g4)State and define the two types of Specific latent heat?
1)Specific latent heat of fusion(Lf) >It is defined as the amount of heat energy needed to change unit mass of a substance from solid to liquid without a change in temperature. OR >The amount of heat required to change 1 kg of the substance from solid to liquid state without a change in temperature. Q = m x Lf 2)Specific latent heat of vaporization(Lv) >It is defined as the amount of energy needed to change unit mass of a substance from liquid to gas. OR >The amount of heat required to change 1 kg of the substance from the liquid to gaseous phase without a change in temperature. Q = m x Lv
Unit 12:- Kinetic Model of Matter (f) FACTORS AFFECTING EVAPORATION?
1)Temperature 2)Area of exposed surface 3)Motion of air 4)Humidity of surrounding air 5)Pressure 6)Nature of liquid
Unit 9:- Transfer of Thermal Energy (h) state and explain the use of the important practical methods of thermal insulation for buildings.
1)Use double glazed windows 2)Place fibreglass on the roof which is a poor conductor of heat 3)Use cavity walls in which air is trapped 4)Place carpets on the floors to minimize heat loss 5)Use colours which are bad emitters of radiation for example white and black colours
Unit 16:- Sound (e) describe a direct method for the determination of the speed of sound in air and make the necessary calculation.
1)Using a measuring tape, Observers A and B are positioned at a known distance, d apart in an open field 2)Observer a fires a starting pistol 3)Observer B, on seeing the flash of the starting pistol, starts the stopwatch and then stops when he hears the sound. The time interval, t is calculated. v = Distance travelled by sound / Time Taken
Unit 23:- Electromagnetic Induction (b)State the factors affecting the magnitude of the induced e.m.f
1)Using a strong magnet with stronger field 2)Using a solenoid with more turns 3)Using solenoid with greater cross sectional area 4)Moving the solenoid/ magnet faster
Unit 10:- Temperature (a) explain how a physical property which varies with temperature may be used for the measurement of temperature and state examples of such properties
1)Volume of a fixed liquid-->Mercury/Alcohol in glass Thermometers 2)Electrical Resistance/ Metal Wire-->Resistance Thermomether 3)Electromotive Force(e.m.f)-->Thermocouple Thermomether 4)Pressure of a gas at constant Volume-->Constant Volume gas thermometer.
Unit 11:- Thermal Properties of Matter (l) list and explain some of the everyday applications and consequences of thermal expansion.
1)We often use hot water to warm up the lid of a jar. This expands the lid (metals expand more than glass), making it easier to remove. 2)Liquid in thermometers expand and contract as the temperature changes. The volume of the liquid at a given temperature is how we read the temperature off of a thermometer. 3)Overhead cables have to be slack so that on cold days when they contract, they won't snap or detach. 4)Expansion joints - these are found on most large bridges.When heat causes the bridge to expand, the two sides of the expansion joint move towards each other. As the temperature cools, they gradually retract. This gives the bridge room for expansion and contraction, preventing the cracking/ deformation of the bridge. 5)Bimetallic strips in thermostats, When you adjust the temperature on a thermostat, you're adjusting how far the bimetal strip has to bend/ straighten out to close the gap.
Unit 9:- Transfer of Thermal Energy (b) describe, in terms of the movement of molecules or free electrons, how heat transfer occurs in solids.
1)When a substance (object) is heated at one end, the particles at the region gains thermal energy and vibrate faster. 2)Thermal energy is transferred along the entire substance (object) by molecular collisions from the hot end of the substance (object) to the cooler end. 3*)Metals contain free electrons that are mobile. 4*)When heated, these free electrons gains KE and will diffuse to the cooler end at high speeds. 5*)In the process, they will collide with atoms at the cooler end and transfer kinetic energy to them.
Unit 11:- Thermal Properties of Matter (i3)When to use 1) Q = mcΔθ and 2) Q = ml
1)When the heat added or removed changes the temperature of an object, the heat is calculated using Q = mcθ 2)When the heat added or removed changes the phase of an object at constant temperature, the heat is calculated using Q = ml
Unit 16:- Sound (k) describe the uses of ultrasound?
1)cleaning 2)quality control 3)pre-natal scanning
Unit 14:- Light (b) describe an experiment to illustrate the law of reflection.
1- Place the paper on the board and fix 2- Place the mirror vertically on the white sheet of paper and trace its edge. 3- Draw a line at right angles to the edge of the edge of the mirror to act as the normal- ON . 4- Stating with angle i as 30 degree , draw an incident ray and place two pins, P and Q along it as shown 5- With your eyes at position shown, place two other pins R and S to coincide with the images of P and Q as seen in the mirror 6- Remove pins R and S and join the dots left with a straight line 7-Measure and record angle r. 8- Repeat procedure 4,5,6 and 7for angles i = 35 degree, 40 degree, 45 degree, 50 degree and 55 degree. Record the results in a table.
Unit 14:- Light (a1)State the laws of reflections?
1. The incident ray, the reflected ray and the normal all lie in the same plane. 2. The angle of incidence, i, is equal to the angle of reflection, r.
Unit 17:-Magnetism and Electromagnetism (a)What is the properties of Magnet?
1. They attract magnetic materials such as Iron Cobalt, nickel and Steel 2. They have 2 poles where magnetic properties are concentrated 3. They always point in the same way when suspended freely 4. Like poles repel and unlike poles attracts
Unit 15:- Electromagnetic Spectrum (c) state that all electromagnetic waves travel with the same high speed in air and state the magnitude of that speed.
1. They transfer energy from one point to another. 2. They are transverse waves. 3. They can travel through vacuum. 4. They travel at the same speed through vacuum, i.e at the speed of light , c = 3 x 10^8 ms-1. 5. They all show wave properties such as reflection, refraction, diffraction and interference. 6. They obey the wave equation, v = fλ.
Unit 11:- Thermal Properties of Matter (c)4)A substance with a small value of specific heat capacity
1. heats up and cools at a faster rate. For example, metal like iron, steel, copper and aluminium is used as pots and pans because they can be quickly heated up when there is only small heat absorption. 2. sensitive to temperature changes A thermometer has low specific heat capacities so it enables heat to be easily absorbed and released even when small quantities of heat are involved.
Unit 11:- Thermal Properties of Matter (c)4)A substance with a high value of specific heat capacity
1. heats up and cools at slower rate. Require more heat to raise its temperature by a specific amount. Poor conductor of heat - handle of pot 2. can absorb a great amount of heat without a high increase in temperature. For example, water acts a heat reservoir as it can absorb a great amount of heat before it boils. Water is used as a cooling agent in a car radiator.
Unit 11:- Thermal Properties of Matter (i2) Specific latent heat of vaporization of water is 2.26 x 106 Jkg-1
2.26 x 106 J of latent heat is needed for 1 kg water to boil to become vapour at 100°C.
Unit 16:- Sound (c) state the approximate range of audible frequencies for the healthy human ear?
20Hz to 20000Hz
Unit 24:- Introductory Electronics (h) describe the action of thermistors and light-dependent resistors and explain their use as input sensors (thermistors will be assumed to be of the negative temperature coefficient type).
THERMISTOR >It is a device whose resistance is affected by temperature -->Resistance Increases when Temperature Decreases >>Used in:- Temperature Control/Measurements, Fire Alarms LIGHT-DEPENDENT RESISTOR >Resistance Decreases as Amount of light Increases(Because Current Increases)
Unit 24:- Introductory Electronics g) discuss the need to choose components with suitable power ratings
The Power rating of a resistor is the maximum rate of dissipation of electrical energy as heat before it is damaged.
Unit 14:- Light (d) state that for reflection, the angle of incidence is equal to the angle of reflection and use this in constructions, measurements and calculations
The angle of incidence, i, is equal to the angle of reflection, r.
Unit 24:- Introductory Electronics (j) describe the action of a diode
The diode is a semiconductor that allows a current to flow easily in one direction only.
Unit 23:- Electromagnetic Induction (c)State Lenz's law?
The direction of the induced current in a solenoid is such that its magnetic effect always oppose the change producing it.
Unit 19:- Current Electricity (d)What is electromotive force(e.m.f)
The electromotive force(e.m.f) of an electrical energy source is defined as the work done by the source in driving unit charge round the circuit
Unit 19:- Current Electricity (h)discuss the advantage of making a battery from several equal voltage of e.m.f arranged in parallel
The energy required to move electric charges through the load will be contributed equally by each cell. Thus each cell only needs to provide half the energy to move the charges through the circuit
Unit 6:- Deformation (c) *recognise the significance of the term "limit of proportionality" for an elastic solid.
The limit of proportionality is the is the point beyond which Hooke's law is no longer true when stretching a material. >The extension is no longer proportional to the force applied.
Unit 5:- Turning Effect of Forces (a) describe the moment of a force in terms of its turning effect and relate this to everyday examples.
The moment(or torque) is the turning effect of the force. 1)Opening and Closing door 2)Turning a steering wheel
Unit 5:- Turning Effect of Forces (b) state the principle of moments for a body in equilibrium.
The principal of moments states that when an object is in equilibrium(balanced), the sum of clockwise moments about any pivot is equal to the sum of anticlockwise moments about the same pivot. >The Principle of Moments states that for an object to be in equilibrium, the sum of all clockwise moment about a pivot is equal to the sum of all anticlockwise moment about the same pivot.
Unit 19:- Current Electricity (I)Define resistance and how it is calculated
The resistance R of a component is defined as the ratio of the potential difference V across it to the current I flowing in it. V = IR
Unit 11:- Thermal Properties of Matter (a) describe a rise in temperature of a body in terms of an increase in its internal energy (random thermal energy).
The rise in temperature of a body is due to an increase in the average kinetic energy of the molecules in the body. Therefore, whenever there is an rise in the temperature of a substance, there must be an increase in the internal energy of the subtance Conversely, if the temperature decreases, there is a decrease in the internal energy of the substance and energy is released. INCREASE IN THERMAL ENERGY:- 1)Temperature rises(increases in Ek) 2)Materials changes state(Increases in Ep)
Unit 26:- Radioactivity (j) make calculations based on half-life which might involve information in tables or shown by decay curves
To measure the half life of a radioactive substance, we have to measure the rate of decay(activity) at different times, by a Gm-Tube
Unit 23:- Electromagnetic Induction (i) discuss the environmental and cost implications of underground power transmission compared to overhead lines
Underground >Expensive overhead lines >Cheapest over long distances
Unit 26:- Radioactivity (k) describe how radioactive materials are moved, used and stored in a safe way.
Uses:- 1)Tracers 2)Penetrating Radiation 3)Power Sources 4)Medical Treatment 5)Archaeological dating >They are kept in LEAD lined boxes
Unit 1:- Physical Quantities, Units and Measurement (c) list the vectors and scalars from distance, displacement, length, speed, velocity, time, acceleration, mass and force.
Vectors:- Force Displacement Velocity Acceleration Weight Moments Scalar:- Length Mass Time Temperature Speed Volume Density Energy Power
Unit 24:- Introductory Electronics (a)What is thermionic emission?
When a certain metal is heated, some of its electrons may gain enough thermal energy to escape from its surface which is known as thermal emission.
Unit 18:- Static Electricity (b)explain that charging of solids involves a movement of electrons.
When a glass rod and a piece of silk is rubbed together, the atoms at the surfaces are disturbed. This causes some electrons from the surface atoms of one object (Glass) to be transferred to the other object(slik). In this case, the glass rod becomes positively charged as it has lost some electrons and the slik becomes negatively charged as it has gained electrons
Unit 11:- Thermal Properties of Matter (j) describe qualitatively the thermal expansion of solids, liquids and gases.
When matter is heated, its particles gain energy, which is exerted as kinetic energy. >In solids, the particles vibrate harder and faster, creating more space between the particles, causing them to expand. This is most visible in metals. This process is thermal expansion. >In liquids, the particles move around faster, weakening the intermolecular forces of attractions, and are thus held less closely together. The liquid expands. If you want, you can test this out yourself, by measuring and comparing the volume of the same mass of water, before and after heating. A common example is the traditional thermometer - as the bulb of the thermometer heats up, the heat is conducted to the liquid. This causes the liquid to expand, forcing it to rise up the thermometer. >In gases, particles move faster as they are heated. If they are heated under constant pressure, the gas particles collide harder with the container surfaces, forcing them out, and allowing the gas to expand. This can be seen when warming the gas in a gas syringe. If gases are heated at a constant volume, however, they do not expand - the gas pressure simply increases. Note that the cooling down of substances tends to have the opposite effect - the particles lose kinetic energy, come closer together, and thus contract.
Unit 3:- Dynamics (a) state Newton's third law
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
Unit 11:- Thermal Properties of Matter (c)3)The physical meaning of specific heat capacity, c
When two objects of equal mass are heated at equal rates, the object with the smaller specific heat capacity will have a faster temperature. When two objects of equal mass are left to cool down, the temperature of the object with smaller heat capacity will drop faster.
Unit 2:- Kinematics (b) recall and use the formula for average speed.
average speed = distance travelled/time taken.
Unit 7:- Pressure (e) recall and use the equation for hydro-static pressure
p(Pa) = ρ(kg/m^3)x g(m/s^2)x h(m)
Unit 14:- Light g) recall and use the equation for refractive index
sin i/sin r = n
Unit 4:- . Mass, Weight and Density (d) recall and use the equation for calculating weight
weight(W) = mass(m) × gravitational field strength(g)
Unit 23:- Electromagnetic Induction (f2)Why does the transformer not work with a d.c power supply?
• A current is induced in the secondary coil only when there is a changing magnetic flux due to a changing primary current. (changes direction and magnitude) • A d.c. power supply gives a constant current in the primary circuit • A constant direct current whose magnitude and direction is constant does not create a changing magnetic flux in the secondary coil. • Therefore electromagnetic induction does not take place.
Unit 23:- Electromagnetic Induction (f)Describe the structure and principle of operation of a simple iron-cored transformer
• A transformer consists of two coils of wire wound round separately on a laminated soft-iron core. • The coil connected to the input voltage is called the primary coil. The coil connected to the output voltage is called the secondary coil. • The purpose of the common iron core is to provide a magnetic field linkage in the secondary coil. • A transformer works on the principle of electromagnetic induction. • When a.c voltage, Vp, is applied to the primary coil of transformer, an alternating current flows through the coil. The soft-iron core is magnetized in one way and then the other. • This means that the magnetic flux linkage in the secondary coil is constantly changing. • An alternating e.m.f is induced across it to produce an a.c voltage, Vs in the secondary coil and a.c current flows through the second coil. • The frequency of the secondary voltage Vs is the same as that of the primary voltage, Vp. • The magnitude of the secondary voltage, Vs, depends on the ratio of the number of turns of the primary and secondary coils.
Unit 23:- Electromagnetic Induction (g)State the relationship between number of turns in coils with voltage in a transformer, (Vp, Np, Vs and Ns)
• According to Faraday's law: Voltage ∝ number of turns in coils (Vp/Vs = Np/Ns) Vp = input (primary) voltage Vs = output (secondary) voltage Np = number of turns in the primary coils Ns = number of turns in the secondary coils
Unit 11:- Thermal Properties of Matter (g1)Why does the temperature remains constant during change of phase?
• During change of phase, the transfer of heat does not cause a change in the kinetic energy of the molecules. • During melting, the heat absorbed is used to break up the bonds between the particles. The particles are freed from their fixed positions and are able to vibrate and move among each other. Their potential energy is therefore increased and the additional energy required is the latent heat of fusion • When a liquids boils, the heat absorbed is used to completely break the bonds between the particles and also to do work against atmospheric pressure when the gaseous vapour expands into the atmosphere. Latent heat of Vaporization is the energy supplied for this purpose. Lv>Lf
Unit 11:- Thermal Properties of Matter (h) explain latent heat in terms of molecular behaviour
• During melting, the heat absorbed is used to break up the bonds between the particles. The particles are freed from their fixed positions and are able to vibrate and move among each other. Their potential energy is therefore increased and the additional energy required is the latent heat of fusion • When a liquids boils, the heat absorbed is used to completely break the bonds between the particles and also to do work against atmospheric pressure when the gaseous vapour expands into the atmosphere. Latent heat of Vaporization is the energy supplied for this purpose. Lv>Lf
Unit 15:- Electromagnetic Spectrum (b) state the colours of the spectrum and explain how the colours are related to frequency/wavelength
• Visible light waves are the only electromagnetic waves we can see. Light can be seen as the colours of rainbow. • Each colour has a different wavelength. • Red has the longest wavelength and violet the shortest. • When all the waves are seen together, they make white light. • When white light shines through a prism, the white light is broken apart into the seven colours of the visible light spectrum. • Red, orange, yellow, green, blue, indigo and violet. (ROYGBIV)
Unit 16:- Sound (b) describe the longitudinal nature of sound waves and describe compression and rarefaction.
• When a tuning fork vibrates, layers of air vibrate and the sound energy is propagated through the air around it in the form of waves. • When the tuning fork moves forwards, the air is compressed. • When the tuning fork moves backwards, the air layers are pulled apart and cause a rarefaction. • Therefore, a series of compression and rarefactions will produce sound.
Unit 11:- Thermal Properties of Matter (i1) Specific latent heat of fusion of ice is 336 000 Jkg-
336 000 J of latent heat is needed for 1 kg ice to melt to become water at 0 °C.
Unit 11:- Thermal Properties of Matter (c)2)What does specific heat of water 4 200 J kg-1°C-1 mean?
4 200 J of heat needs to be supplied to 1 kg of water to produce a 1 °C temperature increase.
Unit 11:- Thermal Properties of Matter (c)1)What does specific heat of aluminium 900 J kg-1°C-1 mean?
900 J of heat needs to be supplied to 1 kg of aluminium to produce a 1 °C temperature increase.
Unit 27:- The Nuclear Atom (e) explain the term nuclide and use the nuclide notation ZXA to construct equations where radioactive decay leads to changes in the composition of the nucleus.
>>A Nuclide is an atom which is specified by its proton number(Z) and Nucleon number(A)
Unit 27:- The Nuclear Atom (d) define the terms proton number (atomic number), Z and nucleon number (mass number), A.
>>Proton Number,Z(atomic number) is the No of Protons in the nucleus >>Nucleon Number, A(Mass Number) is the Sum of Protons and Neutrons in the nucleus
Unit 24:- Introductory Electronics (b)Explain that to cause a continuous flow of emitted requires {1}High positive Potential and {2}very low gas pressure
>A high positive potential is connected to the Anode(+) where the electrons will accelerate to a high speed and they shoot straight through the hole of the anode in a fine beam of electrons, the electron beam are referred as cathode rays as they are produced from the Cathode(-). >There is a very low pressure in order to prevent the electron beam hits the air molecules.
Unit 13:- . General Wave Properties (d) describe transverse and longitudinal waves in such a way as to illustrate the differences between them
>A transverse wave is a wave in which the vibration of particles in the medium is at right angle to the direction of propagation of the wave. The spring is moved sideways. The motion of the particles medium (spring) is at right angles to the direction in which the wave travels. Examples: water waves, light waves >A longitudinal wave is a wave which the vibration of particles in the medium is along (parallel to) the direction of propagation of the wave. The slinky spring moves backwards and forwards to produce a transverse wave. The particles of the medium (spring) move along the direction of the wave. The wave that travels along the spring consists of a series of compression and rarefaction. Examples: sounds waves.
Unit 9:- Transfer of Thermal Energy (e) describe the effect of surface colour (black or white) and texture (dull or shiny) on the emission, absorption and reflection of radiation.
>All BLACK SURFACES are good Absorbers and Emitters of Radiation, But also a Bad reflector of Radiation >All White Surfaces are bad absorbers and emitters of infra-red radiation, But also a good reflector of radiation.
Unit 7:- Pressure (h) describe how a change in volume of a fixed mass of gas at constant temperature is caused by a change in pressure applied to the gas.
>Boyle's law states that for a fixed mass of gas at constant temperature, the volume occupied by the gas is inversely proportional to its pressure. p%1/V k=PV >As the Prew
Unit 12:- Kinetic Model of Matter (d3)Explain the effect of a change in temperature on the pressure of a gas?
>For a fixed mass of gas at constant volume, when the temperature of the gas in the container increases, the molecules move faster and hit the wells more frequently and more violently. This causes the pressure to increases. >Therefore, for a fixed mass at constant volume, gas pressure increases with gas temperature and vice-versa, which is known as Pressure law
Unit 11:- Thermal Properties of Matter (k) describe the relative order of magnitude of the expansion of solids, liquids and gases.
>Gases expand more than liquids which in turn expand more than solids. >This is because the forces of attraction between the molecules in the gas state are very weak so that it is much easier to separate the molecules and increase their average distance of separation.
Unit 11:- Thermal Properties of Matter (b) define the terms heat capacity and specific heat capacity.
>HEAT CAPACITY is defined as the amount of heat energy required by a body for its temperature to rise by 1°C. Q= C x Δθ C = mc >SPECIFIC HEAT CAPACITY of a material is defined as the amount of heat energy required per unit mass of a body for its temperature to increase by 1°C. Specific heat capacity, c = Q/m. Δθ SI unit: = J kg-1°C-1 Q = heat absorbed / released, unit J m = mass of the substance, unit kg θ = temperature difference , unit °C
Unit 3:- Dynamics (b) describe the effect of (2)unbalanced forces on a body.
>If the forces on an object are unbalanced, there will be an Resultant force that will change the object's velocity(either Accelerates or Decelerates) or the object's height. A resultant force will cause a) a stationary object to move b) a moving object to Stop,Move faster, Slow down,Change direction.
Unit 13:- . General Wave Properties (b) state what is meant by the term wavefront
>It is an imaginary line on a wave that joints all points that are in the same phrase OR >A wave front is a line or plane on which the vibration of every points on it are in phase and are at the SAME position from the source of the water.
Unit 23:- Electromagnetic Induction (d)describe a simple form of a.c generator(rotating coil or rotating magnet) and the use of slip rings where needed
>It transforms mechanical energy into electrical energy >It consists of a flat coil rotating between the poles of a permanent magnet. >The two ends of the coil are connected to two slip rings which rotate with the coil. >Each slip ring is always in contact with the same carbon brush.
Unit 14:- Light (n) define the term linear magnification and *draw scale diagrams to determine the focal length needed for particular values of magnification (converging lens only).
>Linear Magnification is the ratio of the height of the image to the height of the object. m=Height of Image/Height of Object >m is also the ratio of the distance of the image from the lens to the distance of the object from the m=D(image from lens)/D(Object from Lens)
Unit 12:- Kinetic Model of Matter (e) describe evaporation in terms of the escape of more energetic molecules from the surface of a liquid
>Molecules in a liquid are at constant motion. These molecules move at different speeds and the average kinetic energy of the molecules increases with temp. >Evaporation occurs when faster moving molecules escapes from the attraction of their neighbours, and leave the surface of the liquid. >The average speed decreases, therefore the average kinetic energy of the molecules remaining in the liquid decreases. Consequently the temperature of the liquid falls.
Unit 5:- Turning Effect of Forces (c) define moment of a force and recall and use the formula and the principle of moments
>Moment = force(F)× perpendicular distance from the pivot(d) > F1d1 = F2d2
Unit 2:- Kinematics (d) discuss non-uniform acceleration.
>Non-uniform acceleration means when its velocity does not change equally in equal-time intervals.
Unit 27:- The Nuclear Atom (c) describe the composition of the nucleus in terms of protons and neutrons
>Nucleus of an Atom is Positively Charged >In the Nucleus--->> Protons(+ve) + Neutrons(no charge)
Unit 13:- . General Wave Properties a) describe what is meant by wave motion as illustrated by vibrations in ropes and springs and by experiments using a ripple tank.
>Process of transferring energy from one location to another which is produced by an oscillating or vibrating motion >When energy is transferred by a wave from a vibrating source to a distant receiver, there is no transfer of matter between the two points
Unit 26:- Radioactivity (n) discuss the dating of objects by the use of 14C.
>Small amount of Radioactive carbon-14 is present in the atmosphere which is absorbed by plants >Plants become slightly Radioactive >When Plants die, the radioactive carbon present inside them will begin to decay >The age of a dead tree can be fund by comparing the count rate of carbon-14 of a dead tree with that of a living tree >Carbon Dating is now used to determine the age of any ancient object.
Unit 27:- The Nuclear Atom (a) describe the structure of the atom in terms of nucleus and electrons.
>The Atom is made up of a very dense core/Nucleus, which is very small when compared to an entire atom >Nucleus-->Protons(+ve) + neutrons(no charge) >>Nucleus--->Positively Charged >Nucleon Number, A(Mass Number)-->Protons + Neutrons >Electrons orbits around Positively Charged Nucleus >Protons=Electrons in an atom
Unit 10:- Temperature (b) explain the need for fixed points and state what is meant by the ice point and steam point
>The fixed points are standard degrees of hotness which are easily obtained ICE POINT >It is the temperature of pure melting ice at standard atmospheric pressure and is assigned the value of O°C STEAM POINT >It is the temperature at which boiling water at standard atmospheric, and is assigned value a value of 100°C
Unit 26:- Radioactivity (h) discuss theories of star formation and their energy production by fusion.
>The low density clouds contracts and split into small fragments, where protostars are formed. It has its own unique gravity and gas particles/dust such as CO and H2 around the protostar falls into its center and become more dense. The Ep of the falling gas is converted to Ek where heat arises in the center of the protostar where the core is sufficiently hot(10 million K), Nuclear Fusion begins. Some of the mass of the hydrogen is converted into energy. The fusion process release so much energy that the pressure created prevents the star from collapsing due to gravitational pressure.
Unit 23:- Electromagnetic Induction (a1)State Faraday's law of electromagnetic induction
>The size of the induced e.m.f is directly proportional to the rate at which the conductor cuts through the magnetic field lines. The size of the induced e.m.f. and thus the induced current and be increased by: 1. moving the magnet or the solenoid at a higher speed 2. increasing the number of turns on the solenoid 3. increasing the strength of the magnetic field through the use of a stronger magnet.
Unit 14:- Light (j) describe the use of optical fibres in telecommunications and state the advantages of their use.
>They are cheaper than metals(e.g Copper) as they are made of glass >Allows high quality Transmissions over long distances with negligible signal loss
Unit 27:- The Nuclear Atom (g) explain, using nuclide notation, how one element may have a number of isotopes
>They are subdivided into stable isotopes and unstable/Radioisotopes >They are used in medicine, industry and agriculture
Unit 22:- Electromagnetism (f)describe the action of a split-ring commutator in a two-pole, single-coil motor and the effect of winding the coil onto a soft iron cylinder.
>To allow the coil moving anticlockwise only! >reverses the connections of the coil with the external circuit after every half cycle, so that the current in the outside circuit always flows in the same direction.
Unit 23:- Electromagnetic Induction (e1)What is a Transformer?
>To change the alternating voltage in the primary coil to a higher or lower alternating voltage in the secondary coil
Unit 24:- Introductory Electronics (e) describe the use of an oscilloscope (the structure of the oscilloscope is not required).
>To measure P.Ds >To display waveform of Alternating Potential Difference >Measure Short Intervals of Time >Compare Frequencies.
Unit 2:- Kinematics (c) state what is meant by uniform acceleration and recall and use its Formula
>Uniform acceleration means when its velocity increases equally in equal time intervals >Acceleration = change in velocity/time taken.
Unit 26:- Radioactivity (g) describe, with the aid of a block diagram, one type of fission reactor for use in a power station.
>Uranium-235 is bombarded with by neutrons to make it unstable, It decays giving out 3 neutrons + Kryton + Barium + Energy. The ueutrons is controlled and is made to collide with other Uranium-235, giving out more energy. Carbon Dioxide is used to carry the energy and convert water to high pressure Steam which is used to drive a turbine to generate Electricity. REACTOR CORE-->CARBON DIOXIDE-->WATER-->HIGH PRESSURE STEAM-->GENERATOR-->TURBINE
Unit 12:- Kinetic Model of Matter (d) explain the pressure of a gas in terms of the motion of its molecules.
>When randomly moving gas molecules hit the walls of a container, they exert a force on the wall. Since Pressure is defined a force per unit area, the force acting on the container gives rise to the gas pressure.
Unit 18:- Static Electricity (a) describe experiments to show electrostatic charging by friction.
>When rubbing plastics rod with fur, electrons from fur flow into plastic rod and hence making the plastic rod to have more electrons than protons. Thus the plastic rod is said to be negatively charged. Small pieces of paper seem to be attracted to the negatively charged plastic rod when they are bought together.
Unit 23:- Electromagnetic Induction (c1)State that the direction of a current produced by an induced e.m.f opposes the change producing it(Lenz's Law) and describe how this law may be demonstrated
>When the magnet is moved towards the solenoid, a current is induced. The current flow in such a way in the solenoid that it try to repel the magnet >When the magnet is moved away from the solenoid, a current is induced. The current flows in such a way in the solenoid that it try to attract the magnet.
Unit 12:- Kinetic Model of Matter (d2)explain the effect of a change in temperature on the volume of a gas at constant temperature
>When the temperature of the gas increases, the molecules move faster and hit the walls more frequently and with greater force which causes the temp. to increase. >Therefore the volume of a fixed mass at constant temperature increases with temperature and vice versa, which is known as charles law
Unit 8:- Energy Sources and Transfer of Energy (i) define work done and use the formula
>Work is said to be done when a force is applied on an object and the object moves in the direction of the force. >(W)ork = (F)orce × (s)distance moved in the line of action of the force.
Unit 7:- Pressure (d) explain quantitatively how the pressure beneath a liquid surface changes with depth and density of the liquid in appropriate examples
A liquid exerts pressure because if its weight. The pressure inside a volume of liquid depends on the depth below the surface of the liquid. The deeper it is, the greater the weight of the overlaying liquid, and the greater the pressure.
Unit 24:- Introductory Electronics (i) describe the action of a variable potential divider (potentiometer).
A potentiometer regulates the P.D across some device. >Contact J divides B and F in 2 parts. >As J is moved towards F, -Length Increases -Resistance Increases -Voltage Increases >With contact J at B, V=0v >With Contact J at F, V=maxV of Battery
Unit 26:- Radioactivity (c) state, for radioactive emissions, their nature, relative ionising effects and relative penetrating powers
ALPHA PARTICLES:- 1)Helium Nucleus 2)Large amount of ionisation 3)Least Penetrating, Stopped by a sheet of Paper BETA PARTICLES:- 1)Fast moving/High energy Electrons 2)Small Amount of Ionisation 3)Stopped by a 5mm thick aluminium sheet GAMMA RAYS:- 1)High Frequency Electromagnetic Radiation 2)Hardly any ionisation 3)Stopped by 2cm thick lead shield
Unit 26:- Radioactivity (d) describe the deflection of radioactive emissions in electric fields and magnetic fields.
ALPHA PARTICLES:- Positively charged BETA PARTICLES:-Negatively charged GAMMA RAYS:-Neutral
Unit 16:- Sound (f) state the order of magnitude of the speeds of sound in air, liquids and solids.
Air = 300m/s Liquids = 1500m/s Solids = 5000m/s
Unit 16:- Sound (h) describe how the reflection of sound may produce an echo
An echo is formed when a sound is reflected off hard, flat surfaces as a large wall or a distant cliff.
Unit 19:- Current Electricity (r)describe the operation of a light-dependent resistor
As the amount of light shining on it increases, the resistance decreases, current increases, thus increasing the light intensity.
Unit 11:- Thermal Properties of Matter (m)Describe qualitatively the effect of a change of temperature on the volume of a gas at constant pressure.
As the temperature increases, the gas molecules gain kinetic energy and move faster. This causes them to collide with the container surfaces harder, forcing the surfaces outwards and allowing the gas to expand. In other words, at constant pressure, the volume is directly proportional to the temperature in Kelvin (K). In formula form, PV/T = k; Where P is the pressure in Pascals (Pa), V is the volume in m3,
Unit 19:- Current Electricity (q)describe the effect of temperature increase on the resistance of a resistor and a filament lamp and draw the respective sketch graphs of current/voltage
As the temperature of the filament increases, the resistance increases. As the temperature of the filament increases, its resistance increases, so the current flowing through the lamp is not directly proportional to the voltage across it.
Unit 11:- Thermal Properties of Matter (d2) describe boiling/condensation in terms of energy transfer without a change in temperature.
Boiling:- >It is a process whereby energy supplied changes the state of a substance from (liquid state to gaseous state) without a change in temperature Condensation:- >Condensation is the change of the physical state of matter from (gaseous state into liquid state) >A pure gaseous substance will condense at the same temperature as its boiling point.
Unit 8:- Energy Sources and Transfer of Energy (f) explain nuclear fusion and fission in terms of energy-releasing processes
Both fission and fusion are nuclear reactions that produce energy, but the applications are not the same. Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy
Unit 4:- . Mass, Weight and Density (e)How weights, therefore masses can be compared?
By using a balance
Unit 8:- Energy Sources and Transfer of Energy (g) describe the process of electricity generation and draw a block diagram of the process from fuel input to electricity output.
CHEMICAL/FUEL ENERGY (a re-grouping of atoms), >(Fuel)Chemical E.-->(Turbine)Thermal E.-->(Generator)Kinetic E.-->(Generator)Electrical E.
Unit 14:- Light (h) define the terms critical angle and total internal reflection and recall and use the formula sin c = 1/n.
CRITICAL ANGLE:- >The critical angle, c is defined as the angle of incidence in the optically denser medium for which the angle of refraction in the optically Less dense medium is 90° Sin(Critical Angle)= 1/n TOTAL INTERNAL REFLECTION:- It is when the light travels from an optically denser medium towards an optically less dense medium for which the angle of incidence is greater than the critical angle.
Unit 2:- Kinematics (h)How to determine the distance travelled for motion with uniform speed or uniform acceleration.
Calculate the area under a speed-time graph
Unit 9:- Transfer of Thermal Energy (c) describe convection in fluids in terms of density changes
Convection is heat transfer due to a density differential within a fluid. >As water's temperature increases in the presence of a heat source, it will become less dense and rise. As it moves up and away from the heat source, it cools and becomes more dense and sinks. >When a fluid is heated at the base, it will expand, become less dense and rise. The cooler fluid at the top being denser, will sink. This continuous, cyclic movement of the fluid known as convection current will eventually heat up the entire whole fluid evenly.
Unit 24:- Introductory Electronics (d)state that the flow of electrons {electron current} in magnetic fields.
Conventional current flows in opposite direction to electrons. By applying Fleming's Left hand Rule, the force acting on the beam is downwards and the path of the beam is circular.
Unit 24:- Introductory Electronics (k) describe the action of a light-emitting diode
Current Flows in Only 1 direction and Emits Light.
Unit 19:- Current Electricity (a) state that a current is a flow of charge and that current is measured in Amperes.
Current is a measure of the rate of flow of electric charge Q through a given cross section of a conductor.
Unit 2:- Kinematics (e) recall that deceleration is a negative acceleration
Deceleration= -(-Acceleration) Deceleration= +Acceleration m/s2, IN THE DIRECTION OF MOTION.
Unit 14:- Light (l) define the term focal length.
Distance between the focal point , F and optical centre, C on the lens.
Unit 19:- Current Electricity (e,f)How is e.m.f and Volts are measured.
E.m.f = Work Done(J) / Charge(C) OR E(J) = V(E.m.f) x Q
Unit 26:- Radioactivity (l) discuss the way in which the type of radiation emitted and the half-life determine the use for the material
Each different elements emits different intensities of radiation, thus could be used for the right type of type of material with specific purpose!
Unit 23:- Electromagnetic Induction (h) state the advantages of high voltage transmission
Electrical power can be transmitted more economically at high voltages and low current. Electrical power is transmitted at a high voltage so that • The current in the cables is smaller • The loss of power due to heating of the cables is minimized.
Unit 8:- Energy Sources and Transfer of Energy (l) discuss the usefulness of energy output from a number of energy conversions.
Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation), or heat.
Unit 6:- Deformation (d) calculate extensions for an elastic solid using proportionality
F=ke F: Tension;force k: N/m; force per unit extention e: (L-Lo)-->(Stretched length-Original Length)
Unit 3:- Dynamics (d) recall and use the equation of Newton's Second Law of motion.
Force(N)= Mass(Kg) x Acceleration(m/s^2) Notes:- (1)When the resultant force on a Mass is 0N, the acceleration is also 0m/s^2 which means that (a)either the object is at rest and remains at rest. (b)the object is moving at a constant speed and continues to move at that constant speed. (2)The direction of the force is the same as the direction of the object's acceleration.
Unit 3:- Dynamics (e) explain that friction is a force that impedes motion and produces heating.
Friction is a force which opposes motion between two surfaces in contact, which is still needed for motion to be possible. >It originates from the roughness of surfaces, when two surfaces rubs against each other, it impedes motion and produces heating, there is a force of attraction between the object. This force of attraction gives rise to friction.
Unit 4:- . Mass, Weight and Density (c)What is Gravitational Field?
Gravitational field is a region in which a mass experiences a force due to gravitational attraction
Unit 18:- Static Electricity (i)state what is meant by "earthing" a charged object.
Grounding is the process of removing the excess charge on an object by means of the transfer of electrons between it and another object of substantial size. When a charged object is grounded, the excess charge is balanced by the transfer of electrons between the charged object and a ground.
Unit 26:- Radioactivity (i) explain what is meant by the term half-life.
Half life of a sample of radioactive substance is defined as the time for half of the unstable nuclei to decay >Radioactive elements with longer half-life are more stable
Unit 6:- Deformation (b) *plot, draw and interpret extension-load graphs for an elastic solid and describe the associated experimental procedure.
Hooke's law states that, within the limit of proportionality, the extension produced in an elastic material is directly proportional to the force applied. F=ke
Unit 7:- Pressure (g) describe and explain the transmission of pressure in hydraulic systems with particular reference to the hydraulic press and hydraulic brakes on vehicles
Hydraulic systems work by using liquids under pressure. They make use of 2 properties of liquids. 1)Liquids are incompressible 2)If pressure is applied to an enclosed liquid, the pressure is transmitted to all parts of the liquid. F1/A1=F2/A2 >A small force F1, applied on one disc gives rise to a much bigger force F2 on the second disc
Unit 17:-Magnetism and Electromagnetism (f)(g)State the differences between the properties of temporary magnets(iron)and permanent magnets(steel)?
IRON 1)Easily magnetized and Demangnetized 2)can be magnetized by a weak magnetic field 3)When mixed with other Metals, powerful temporary magnets can be made 4)Used in Electromagnet, Transformer cores and Magnetic Shields STEEL 1)Harder to magnetise 2)Requires a strong magnetic field to magnetise 3)Very good for permanent magnet 4)Ussd in bar magnets
Unit 9:- Transfer of Thermal Energy (g) describe how heat is transferred to or from buildings and to or from a room.
If the inside of a building is hot and the outside is cold, heat will be lost from the inside to the outside.
(h)Explain the choice of material for and, use of, magnetic screening
If we want to shield a piece of equipment from undesirable magnetic fields, we must house it in a thick walled iron container.
Unit 23:- Electromagnetic Induction (g2)What is the relationship between output power and input power of an ideal transformer(100% efficient)?
In an ideal transformer, there is no energy loss during the process of transforming the voltage. [Power supplied to = [Power used in the the primary coil] secondary coil] Input power = Output power VpIp = VsIs
Unit 8:- Energy Sources and Transfer of Energy (m) define power and recall and use the formula
In physics, power is the rate of doing work, the amount of energy transferred per unit time Power(J/s) = work done/time taken.
Unit 8:- Energy Sources and Transfer of Energy (b) state the principle of the conservation of energy and apply this principle to the conversion of energy from one form to another.
In physics, the law of conservation of energy states that the total energy of an isolated system remains constant, it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.
Unit 26:- Radioactivity (m) discuss the origins and effect of background radiation.
In theabsence of a radioactive source in front of a GM Tube, the counter connected to the GM Tube will register a small but nearly constant count rate, because of Background radiation SOURCES 1)Radioactive Substance in the Earth's Crust 2)Emission of radioactive gas from the Earth 3)Cosmic Rays from Outer Space bombarding Earth 4)Presence of small tacers of many naturally Occurring Radioactive materials in the human body
Unit 4:- . Mass, Weight and Density (b)What is inertia?
Inertia of an object refers to the reluctance of the object to change its state of rest or motion
Unit 27:- The Nuclear Atom (f) define the term isotope.
Isotopes of an element are atoms which have the same proton number but different nucleon numbers NATURAL-->Found in Nature like Hydrogen, Carbon Artificial-->These are Isotopes, manucfactured in nuclear laboratories by bombardng lighter nuclides with protons, neutrons or alpha particles
Unit 2:- Kinematics (i) state that the acceleration of free-fall for a body near to the Earth.
It is constant and is approximately 10 m/s^2
Unit 16:- Sound (j) define ultrasound
It is sounds with frequencies above the upper limit of the human range of audibility.
Unit 8:- Energy Sources and Transfer of Energy (c) state that kinetic energy is given by (formula) and that gravitational potential energy is given by (formula), and use these equations in calculations.
KINETIC ENERGY of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. Ek = ½mv 2 POTENTIAL ENERGY is the energy that is stored in an object due to its position relative to some zero position. An object possesses gravitational potential energy if it is positioned at a height above (or below) the zero height. Ep = mgh
Unit 11:- Thermal Properties of Matter (g2) define the terms latent heat and specific latent heat.
LATENT HEAT:- It is defined as the amount of energy required by a substance for it to change state SPECIFIC LATENT HEAT:- >It is the amount of energy needed to change the state of unit mass of a substance. OR >The amount of heat required to change the phase of 1 kg of the substance at a constant temperature Q = ml unit for l : J kg-1 Q = latent heat absorbed or released by the substance m = mass of the substance
Unit 10:- Temperature (d) describe the structure and action of liquid-in-glass thermometers (including clinical) and of a thermocouple thermometer, showing an appreciation of its use for measuring high temperatures and those which vary rapidly
LIQUID-IN-GLASS THERMOMETHER 1. The bulb of the thermometer contains a fixed mass of mercury. The volume of the mercury increases when it absorbs heat. 2. The mercury expands and rises in the capillary tube. The length of the mercury column in the capillary tube indicates the magnitude of the temperature. >A thermocouple consists of two types of wires made of different metals. The ends of the wires are joined to form two junctions. >When the two junctions are at different temperature (one hot and one cold), a small voltage (e.m.f) is produced. >The greater the difference, the greater the voltage produced across the two junctions. That is, the voltage produced is proportional to the temperature difference. >By knowing one reference temperature and measuring the voltage, the unknown temperature can be found. E1/ΔO1 = E2/ΔO2
Unit 14:- Light (q) describe the correction of short-sight and long-sight
LONG SIGHTED >A person who see distant objects clearly but cannot focus near object. >Eyeball too small and eyes lens too thin >Rays of light from a close object are focussed towards a point behind his retina >Should wear a Converging lens SHORT SIGHTED >Can see near Objects clearly but cannot focus distant objects >Eyeball too long or eye lens too thick >Rays of light from a distant objects are focused in front of the retina. >Should wear a Diverging lens
Unit 16:- Sound (g) explain how the loudness and pitch of sound waves relate to amplitude and frequency.
LOUDNESS:- • The loudness of the sound depends on its amplitude. • If the amplitude is increased, the loudness increases. PITCH • A high pitch sound corresponds to a high frequency and a low pitch sound corresponds to a low frequency of vibration
Unit 17:-Magnetism and Electromagnetism (d)Describe electrical methods of magnetisation and demangnetisation.
MAGNETISATION 1. Stroking Method The unmagnetised steel bar being stroke several times by a permanent magnet. The steel bar is stroked every time by the same pole(N pole) of permanent magnet, the steel bar would eventually become a permanent magnet by magnetic induction 2. Electromagnet A steel bar is wrapped with a cylindrical coil of insulated copper wire is known as solenoid, when a current (DC) passes through the solenoid, the steel bar would become a magnet after a while, it would also produce a strong magnetic field.--use Right hand grip Rule to know the N+S of the electromagnet DEMAGNETISATION 1. Dropping or knocking 2. Heating it 3. Applying a rapid reversing magnetic field around it(Wind a coil of wire around the magnet and pass an AC through it)
Unit 4:- . Mass, Weight and Density (f) describe how to measure mass and weight by using appropriate balances.
MASS >Measured by a beam balance or Calibrated electronic balance WEIGHT >Measured by a spring or compression balance
Unit 11:- Thermal Properties of Matter (e) state the meaning of melting point and boiling point
MELTING POINT is the temperature at which a solid changes state to become a liquid >A pure substance will freeze/solidify at a temperature equal to its melting point. BOILING POINT is at which a liquid changes state to become a gas. >A pure gaseous substance will condense at the same temperature as its boiling point.
Unit 17:-Magnetism and Electromagnetism (b) Describe induced magnetism
Magnetic induction is the process of inducing magnetism is an unmagnetised ferromagnetic material without any contact with the magnet.
Unit 4:- . Mass, Weight and Density (a)Define Mass
Mass is a measure of the amount of substance in a body
Unit 17:-Magnetism and Electromagnetism (c) State the differences between magnetic, non-magnetic and magnetised materials
Materials that are attracted by a magnet are called magnetic materials like Iron, Steel, Cobalt and Nickel Materials that are not attracted by a mangent magnet are called non-magnetic, like brass, copper, aluminium, wood, plastics
Unit 6:- Deformation (a)State the effects when a force is applied on a material?
May cause a change in 1)Shape 2)Size >To cause a deformation
Unit 11:- Thermal Properties of Matter (d1) describe melting/solidification in terms of energy transfer without a change in temperature.
Melting:- >It is a process whereby the energy supplied changes the state of a substance from a (solid to a liquid state), without a change in temperature Solidification:-{Freezing} "Freeze" has the same meaning as "solidify" except that "Freeze" is usually reserved for colder temperatures >(Liquid to Solid) E.g Wax solidifies at 25°C whereas water freezes at 0°C >A pure substance will freeze/solidify at a temperature equal to its melting point.
Unit 9:- Transfer of Thermal Energy (a) describe how to distinguish between good and bad conductors of heat.
Metals and stone are considered good conductors since they can speedily transfer heat, whereas materials like wood, paper, air, and cloth are poor conductors of heat.This tells us that wood and plastic are bad conductors of heat while metal is a good conductor of heat. Thermal energy always flows from a region of higher temperature to a region of lower temperature.
Unit 14:- Light (a) define the terms used in reflection including normal, angle of incidence and angle of reflection
Mirror works because it reflects light.. >The light ray that strikes the surface of the mirror is called incident ray. >The light ray that bounces off from the surface of the mirror is called reflected ray. >The normal is a line perpendicular to the mirror surface where the reflection occurs. >The angle between the incident ray and the normal is called the angle of incidence, i >The angle between the reflected ray and the normal is called the angle of reflection, r.
Unit 26:- Radioactivity (f) explain the processes of fusion and fission.
NUCLEAR FUSION >Nuclear Fusion is the process whereby lighter nuclides fuse together to form a heavier nucleus with the release of energy -->Fusion of the nuclei of deuterium. The fusion of the 2 nuclei of deuterium can result in a helium nucleus. NUCLEAR FISSION >Nuclear Fission is the process whereby heavy unstable nuclides beak up to produce energy -->Uranium-235 is bombarded by neutrons, it forms uranum-236 which is Unstable and therefore breaks down into Barium , Krpton and 3 neutrons >The 3 fast moving neutrons are mode to slow down to produce further fission by colliding with other Uranium-235 nuclei to form Uranium-236 which again undergoes fission and generates more fission fragments, more neutrons and more energy
Unit 24:- Introductory Electronics (c)Describe the deflection of an electron beam by electric fields.
Negatively charged electrons emitted in thermionic emission are attracted towards the positive plate.
Unit 3:- Dynamics (b) describe the effect of (1)balanced forces on a body.
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. CASES:- (1)An object that is at rest will stay at rest unless a force acts upon it. Eg:- Book on a Table (2)An object that is in motion will not change its velocity unless a force acts upon it. Eg:- Plane Note:- No resultant force does not mean that there are no forces acting on the body. It just means that all the forces are balanced.
Unit 3:- Dynamics (c) describe the ways in which a force may change the motion of a body.
Newton's Second Law states that the resultant force acting upon an object is equal to the product of the mass and the acceleration of the object. A resultant force will cause a) a stationary object to move b) a moving object to Stop,Move faster, Slow down,Change direction.
Unit 19:- Current Electricity (n)State Ohm's law and discuss the temperature limitation on Ohm's law
Ohm's law states that the current passing through a metallic conductor is directly proportional to the potential difference across its ends, provided the physical conditions such as temperature are constant V/I = R = Constant
Unit 7:- Pressure (f) describe the use of a manometer in the measurement of pressure difference.
P(Gas)=P(Height, h) + P(atm)
Unit 7:- Pressure (i) recall and use the formula for Boyle's equation for Gas at constant temperature!
P1V1=P2V2
Unit 17:-Magnetism and Electromagnetism (g)Decribe the uses of Permanent magnet and electromagnet!
PERMANENT MAGNETS 1)Moving coil galvanometer 2)Moving Coil Loudspeakers 3)Magnetic door catches 4)D.C motors and A.C generators ELECTROMAGNET 1)Electric bells 2)Simple Magnetic relays 3)Reed switches 4)Reed Relays
Unit 7:- Pressure (a) define the term pressure in terms of force and area, and do calculations using the equation
Pressure is defined as the force acting per unit area. Pressure(N/m^2) = force(N)/area(m^2)
Unit 11:- Thermal Properties of Matter (c) recall and use the formula thermal energy=??
Q = mcΔθ
Unit 11:- Thermal Properties of Matter (i) calculate heat transferred in a change of state using the formula thermal energy = mass × specific latent heat
Q = ml unit for l: J kg-1 Q = latent heat absorbed or released by the substance m = mass of the substance
Unit 19:- Current Electricity (b)recall and use the equation that measure charge
Q(A)= I(C) X t(s)
Unit 9:- Transfer of Thermal Energy (d) describe the process of heat transfer by radiation.
Radiative heat transfer does not require a medium to pass through; thus, it is the only form of heat transfer present in vacuum. It uses electromagnetic radiation (photons), which travels at the speed of light and is emitted by any matter with temperature above 0 degrees Kelvin
Unit 26:- Radioactivity (b) state and explain the random emission of radioactivity in direction and time.
Radioactive Decay is not affected by Chemical Combinations, Temperature, Pressure and other External Conditions.(Spontaneous) >Radioactive emission occur randomly over pace and time, that it is not possible to predict where and when radioactive emissions will take place
Unit 26:- Radioactivity (e) explain what is meant by radioactive decay.
Radioactive Decay is the natural process whereby unstable nuclides disintegrates in order to become more stable
Unit 24:- Introductory Electronics (l) describe and explain the action of relays in switching circuits.
Relays are switches that open and close circuits electromechanically or electronically. Relays control one electrical circuit by opening and closing contacts in another circuit. A relay is a special type of switch turned on and off by an electromagnet A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. The heart of a relay is an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it).
Unit 19:- Current Electricity (o)*use qualitatively the proportionality between resistance and the length and the cross-sectional area of a wire
Resistance R depends on:- 1)Length, l >The longer the wire, the greater the resistance 2)Cross-sectional Area, A / Thickness >The larger the cross-sectional area of wire, the lower its resistance 3)Type of material >The lower the resistivity, the better the conductor of electricity. R = p(Ω⋅m) x l(m)/A(m^2)
Unit 10:- Temperature (e) describe and explain how the structure of a liquid-in-glass thermometer affects its sensitivity, range and linearity.
SENSITIVITY:- 1)The thinner the diameter, the greater the sentivity! 2)The greater the volume, the greater the expansion, the greater the sensitivity. RANGE:- 1)length of the stem 2)Volume of liquid 3)Diameter of the capillary tube
Unit 10:- Temperature (c) discuss sensitivity, range and linearity of thermometers.
SENSITIVITY:- A sensitive thermometer gives a more noticeable expansion (large increase in the length of the mercury thread) for small changes in temperature. >Amount of change in thermometric property per unit change in temperature 1)The thinner the diameter, the greater the sentivity! 2)The greater the volume, the greater the expansion, the greater the sensitivity. RANGE:- The maximum and Minimum temperatures that the thermometer can measure. 1)length of the stem 2)Volume of liquid 3)Diameter of the capillary tube LINEARITY:- A thermometric property is said to be linear when it changes uniformly with equal changes in temperature.
Unit 12:- Kinetic Model of Matter (b) describe qualitatively the molecular structure of solids, liquids and gases, relating their properties to the forces and distances between molecules and to the motion of the molecules.
SOLID:- 1)Arranged close together in a regular pattern 2)Cannot be compressed as there is little space between the molecules LIQUID:- 1)Molecules are slightly further apart than solids 2)Cannot be compressed as there is a very little space between the molecules. GAS:- 1)Molecules are fast apart 2)There is a lot of space between them.
Unit 12:- Kinetic Model of Matter (c) describe the relationship between the motion of molecules and temperature.
SOLID:- 1)Balanced forces between the molecules which help them in fixed positions 2)Molecules only vibrate about fixed position 3)Strong attractive forces 4)When heated, gain kinetic energy, separation between molecules increases slightly and the solid expands LIQUID:- 1)Molecules vibrates, attracting and repelling one another. 2)There is forces between molecules holding them in a fixed position 3)Attractive forces between the liquids make it difficult to leave the liquid 4)When Heated, It vibrates and move vigorously, thus it expands slightly only to a very slight extend GAS 1)Moves randomly at high speeds 2)Molecules are far apart that the intermolecular forces become negligible
Unit 13:- . General Wave Properties (c) define the terms speed, frequency, wavelength and amplitude and recall and use the formula velocity = frequency × wavelength.
SPEED The speed of a wave is the measurement of how fast a crest is moving from a fixed point. SI unit is ms-1. FREQUENCY The number of waves produced in one second. SI unit is Hertz (Hz) WAVELENGTH The distance between two successive crests or two successive troughs AMPLITUDE The maximum displacement from its equilibrium position. Amplitude relates to loudness in sound and brightness in light. SI unit: meter, m
Unit 14:- Light (f) describe experiments to show refraction of light through glass blocks
STEPS 1)Place the rectangular block on a sheet of paper, trace the shape of the glass ABCD on the paper. 2)Remove the Glass block and draw perpendicular lines NR at O. 3)Use pins and protractor to make angles of incidence on the soft board 4)Place the glass block 5)Push 2 pins P1 and P2 located along 30 to the normal 6)Look through the other side CD at position E and place Pins P3 and P4 such that images P1 and P2 appear behind them. 7)Remove the pins and block and join P3 and P4 to meet CD at S. Join OS, the path of refracted ray in the glass block 8)Measure r and g 9)Repeat steps 5 to 8 with different angles
Unit 1:- Physical Quantities, Units and Measurement (a) define the terms scalar and vector
Scalar Quantity is a physical quantity that have magnitude and a unit. Vector quantity is a physical quantity that have magnitude, a unit and a DIRECTION
Unit 8:- Energy Sources and Transfer of Energy (k) discuss the efficiency of energy conversions in common use, particularly those giving electrical output
So the ratio of energy output to energy input is always unity, or 100%. The meaning of the word 'useful' depends on the purpose of the device. For example, if the device is an electric heater, the useful energy output is heat, and the energy input is electricity. Electricity is converted to heat.
Unit 12:- Kinetic Model of Matter (a) state the distinguishing properties of solids, liquids and gases.
Solids:- 1)Fixed shape and Volume 2)Not compressible 3)Does not flow Liquids:- 1)Fixed volume but no fixed shape 2)Takes the shape of the container 3)Not easily compressible 4)Flows easily Gas:- 1)No fixed shape and no Fixed volume 2)Takes the shape and volume of the container 3)Highly compressible 4)Flows easily
Unit 16:- Sound (d) explain why a medium is required in order to transmit sound waves and describe an experiment to demonstrate this.
Sound is a mechanical wave is a wave that propagates as an oscillation of matter, and therefore transfers energy through a medium.A mechanical wave requires an initial energy input. Once this initial energy is added, the wave travels through the medium until all its energy is transferred.
Unit 16:- Sound (a) describe the production of sound by vibrating sources.
Sound waves are produced when a vibrating object causes the air molecules around it to vibrate.
Unit 2:- Kinematics (a) state what is meant by speed and velocity.
Speed is defined as the distance moved per unit time. Velocity is defined as the change in displacement per unit time.
Unit 5:- Turning Effect of Forces (f) describe qualitatively the effect of the position of the centre of mass on the stability of simple objects.
Stability refers to the ability of an object to return to its original position after it has been tilted slightly. To make a body more stable:- 1)Lowering its center of gravity 2)Increasing the area of its base
Unit 1:- Physical Quantities, Units and Measurement (b) determine the resultant of two vectors by a graphical method.
Step 1: Choose and appropriate scale Step 2: Draw each vector by using the chosen scale Step 3: Complete the parallelogram by drawing parallel lines Step 4: Draw diagonals between the 2 vectors Step 5: Measure the length of diagonals and use scale to calculate the magnitude of the resultant. Step 6: Using a protractor, measure the angle in the resultant and the one of the vector to obtain the direction of the resultant.
Unit 23:- Electromagnetic Induction (f23)Differentiate between an Step-up Transformer and a Step-Down Transformer?
Step-up Transformer:- >Change Voltage in Primary Coil to a higher Voltage in the secondary coil >More turns in the Secondary Coil >then Vs is greater than Vp Step-Down Transformer:- >Change Voltage in Primary Coil to a lower voltage in the secondary coil >Less turns in secondary coil >then Vs is lower than Vp
Unit 5:- Turning Effect of Forces d) describe how to verify the principle of moments.
Steps 1)Pivot the meter rule at 50 cm mark. The meter rule should be able to rotate freely 2)Hand w1= 0.5N and w2=0.4N on the opposite sides of the pivot with thread 3)Balance the system by adjusting the distances d1 and d2. Record the values d1 and d2 4)Repeat the experiment for another three sets of w1 and w2 5)Record the coresponding values of d1 and d2 6)Calculate the anticlockwise moment w1 x d1 and clockwise moment w2 x d2 and tabulate the results.
Unit 5:- Turning Effect of Forces (e) describe how to determine the position of the centre of mass of a plane lamina
Steps:- 1)Make 3 small holes near the edge of the lamina 2)Suspend the lamina through one of the holes using a pin 3)Hand a plumb line on the pin in front of the lamina. 4)When the plumb is steady, draw a line on the lamina over a plumb line 5)Repeat the above steps for 2 more holes. 6)The point of intersection X of the 3 lines is the position of the center of gravity.