Co-ordinated Sciences (Double Award) — Physics

Science 0973 — specification explorer

All 221 specification statements from the official Cambridge International specification, as printed.

Paper/unit applicability has not been derived for this course yet — the statements below are the parsed specification, as printed.

1. Motion, forces and energy

1. Physical quantities and measurement techniques

P1.1.1Describe the use of rulers and measuring cylinders to find a length or a volume
P1.1.2Describe how to measure a variety of time intervals using clocks and digital timers
P1.1.3Determine an average value for a small distance and for a short interval of time by measuring multiples (including the period of oscillation of a pendulum)
P1.1.4Understand that a scalar quantity has magnitude (size) only and that a vector quantity has magnitude and direction
P1.1.5Know that the following quantities are scalars: distance, speed, time, mass, energy and temperature
P1.1.6Know that the following quantities are vectors: force, weight, velocity, acceleration and gravitational field strength

2. Motion

P1.2.1Define speed as distance travelled per unit time; recall and use the equation
P1.2.2Recall and use the equation total distance travelled average speed = total time taken
P1.2.3Sketch, plot and interpret distance–time and speed–time graphs
P1.2.4Know that an object moving with increasing speed is accelerating, and that an object moving with decreasing speed is decelerating
P1.2.5
Determine, qualitatively, from the shape of a distance–time graph or speed–time graph when an object is: (c). accelerating (d). decelerating:
- (a) . at rest
- (b) .moving with constant speed
P1.2.6Calculate speed from the gradient of a straight-line section of a distance–time graph
P1.2.7Calculate the area under a speed–time graph to work out the distance travelled for motion with: (a). constant speed (b). constant acceleration
P1.2.8Define velocity as speed in a given direction
P1.2.9Define acceleration as change in velocity per unit time; recall and use the equation
P1.2.10Determine from given data or the shape of a speed–time graph when an object is moving with: (a). constant acceleration (b). changing acceleration
P1.2.11Calculate acceleration from the gradient of a straight-line section of a speed–time graph
P1.2.12Know that deceleration is a negative acceleration and use this in calculations
P1.2.13Know that the acceleration of free fall g for an object near to the surface of the Earth is approximately constant and is approximately

3. Mass and weight

P1.3.1State that mass is a measure of the quantity of matter in an object
P1.3.2State that weight is the gravitational force on an object that has mass
P1.3.3Define gravitational field strength g as the gravitational force per unit mass; recall and use the equation and know that near to the surface of the Earth, g is approximately 9.8 N / kg
P1.3.4Describe, and use the concept of, weight as the effect of a gravitational field on a mass
P1.3.5Know that gravitational field strength is equivalent to the acceleration of free fall

4. Density

P1.4.1Define density as mass per unit volume; recall and use the equation
P1.4.2Describe how to determine the density of a liquid, of a regularly shaped solid and of an irregularly shaped solid which sinks in a liquid (volume by displacement), including appropriate calculations
P1.4.3Determine whether an object floats or sinks based on density data

5. Forces

P1.5.1Know that forces may produce changes in the size, shape and motion of an object
P1.5.1aDescribe the moment of a force as a measure of its turning effect and give everyday examples
P1.5.1bUnderstand what is meant by centre of gravity and know its position for regularly shaped objects (limited to rectangular blocks, spheres and cylinders)
P1.5.2Determine the resultant of two or more forces acting along the same straight line
P1.5.2aDefine the moment of a force as moment = force × perpendicular distance from the pivot; recall and use this equation
P1.5.2bDescribe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina
P1.5.3Describe friction as the force between two surfaces that may impede relative motion and produce heating
P1.5.3aState that, when there is no resultant force and no resultant moment, an object is in equilibrium
P1.5.3bDescribe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects P1.6.1 Energy
P1.5.4Know that friction (drag) acts on an object moving through a liquid
P1.5.5Know that friction (drag) acts on an object moving through a gas (e.g. air resistance)
P1.5.6Know that an object either remains at rest or continues in a straight line at constant speed unless there is a resultant force on the object P1.5.2 Turning effect of forces
P1.5.7Recall and use the equation F = ma and know that the resultant force and the acceleration are in the same direction
P1.5.8Sketch, plot and interpret load–extension graphs for an elastic solid and describe the associated experimental procedures
P1.5.9Define the spring constant as force per unit extension; recall and use the equation
P1.5.10Define and use the term ‘limit of proportionality’ for a load–extension graph and identify this point on the graph (an understanding of the elastic limit is not required) with one force each side of the pivot, including balancing of a beam

6. Energy, work and power

P1.6.1State that energy may be stored as kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)
P1.6.1aUnderstand that mechanical or electrical work done is equal to the energy transferred
P1.6.1bmv 2 gravitational potential energy Δ E = mg Δ h
P1.6.1c
Describe how useful energy may be obtained, or electrical power generated, from: hydroelectric dams (f). light from the Sun (solar cells) (g). infrared and other electromagnetic waves from the Sun to heat water (solar thermal collectors) including references to a boiler, turbine and generator where they are used:
- (a) . fossil fuels
- (b) .biofuels
- (c) . water, including waves, tides, and
- (d) .geothermal resources
- (e) . nuclear fission
- (h) .wind (wind turbines)
P1.6.1dDefine power as work done per unit time and also as energy transferred per unit time; recall and use the equations
P1.6.2Describe how energy is transferred between stores during events and processes, including examples of transfer by forces (mechanical work done), electrical currents (electrical work done), heating and by electromagnetic, sound and other waves
P1.6.2aRecall and use the equation for mechanical working W = Fd = Δ E
P1.6.2bGive advantages and disadvantages of each method in terms of renewability, availability, reliability, scale and environmental impact
P1.6.3Know the principle of conservation of energy and apply this principle to simple examples including the interpretation of simple flow diagrams (Sankey diagrams are not required) P1.6.2 Work
P1.6.3aUnderstand, qualitatively, the concept of efficiency of energy transfer P1.6.4 Power
P1.6.4Recall and use the equation for kinetic energy
P1.6.4aKnow that radiation from the Sun is the main source of energy for all our energy resources except geothermal, nuclear and tidal
P1.6.5Know that energy is released by nuclear fusion in the Sun (detailed knowledge of the process of fusion is not required)
P1.6.6Know that energy is released by nuclear fission in nuclear reactors (detailed knowledge of the process of fission is not required)
P1.6.7Define efficiency as: useful energy output (a). efficiency = × 100% total energy input useful power output (b). efficiency = × 100% total power input recall and use the equations

7. Pressure

P1.7.1Describe how pressure varies with force and area in the context of everyday examples
P1.7.2Define pressure as force per unit area; recall and use the equation P2.1.1 States of matter

2. Thermal physics

1. Kinetic particle model of matter

P2.1.1State the distinguishing properties of solids, liquids and gases
P2.1.1aDescribe the structure of solids, liquids and gases in terms of the arrangement, separation and motion of the particles and represent these states using simple particle diagrams
P2.1.1bDescribe qualitatively, in terms of particles, the effect on the pressure of a fixed mass of gas of: (a). a change of temperature at constant volume (b). a change of volume at constant temperature
P2.1.2Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas changes are not required) P2.1.2 Particle model
P2.1.2aDescribe the relationship between the motion of particles and temperature
P2.1.3Know that the random motion of particles (e.g. smoke particles or pollen grains, that can be viewed with a light microscope) in a suspension is evidence for the kinetic particle model of matter
P2.1.4Know that the forces and distances between particles and the motion of the particles affect the properties of solids, liquids and gases
P2.1.5Describe and explain this motion (sometimes known as Brownian motion) in terms of random collisions between particles in the suspension and the much smaller, fast- moving particles of the gas or liquid
P2.1.6Describe the pressure of a gas in terms of the forces exerted by particles colliding with surfaces, creating a force per unit area

2. Thermal properties and temperature

P2.2.1Describe, qualitatively, the thermal expansion of solids, liquids and gases at constant pressure P2.2.2 Melting, boiling and evaporation
P2.2.1aKnow the melting and boiling temperatures for water at standard atmospheric pressure (limited to Celsius only)
P2.2.2Describe condensation and solidification (freezing) in terms of particles
P2.2.2aExplain some of the everyday applications and consequences of thermal expansion evaporation and air movement over a surface affect evaporation
P2.2.3Describe evaporation in terms of the escape of the more energetic particles from the surface of a liquid
P2.2.4Know that evaporation causes cooling of a liquid
P2.2.5Describe melting and boiling in terms of energy input without a change in temperature P2.3.1 Conduction

3. Transfer of thermal energy

P2.3.1Identify and give examples of typical good thermal conductors and bad thermal conductors (thermal insulators)
P2.3.1aKnow that convection is an important method of energy transfer in liquids and gases
P2.3.1bKnow that thermal energy transfer by thermal radiation does not require a medium and is mainly due to infrared radiation
P2.3.1cIdentify and explain some of the basic everyday applications and consequences of conduction, convection and radiation
P2.3.2Describe thermal conduction in solids in terms of atomic or molecular lattice vibrations and also in terms of the movement of delocalised (mobile) electrons in metallic conductors
P2.3.2aDescribe convection in liquids and gases P2.3.3 Radiation
P2.3.2bDescribe the effect of surface colour (black or white) and texture (dull or shiny) on the emission, absorption and reflection of thermal radiation P2.3.4 Consequences of thermal energy transfer
P2.3.3Explain convection in liquid and gases in terms of density changes affected by the radiation absorbed by the Earth and the radiation emitted by the Earth
P2.3.4Describe experiments to distinguish between good and bad emitters of thermal radiation
P2.3.5Describe experiments to distinguish between good and bad absorbers of thermal radiation

3. Waves

1. General properties of waves

P3.1.1Know that waves transfer energy without transferring matter
P3.1.2Describe what is meant by wave motion as illustrated by vibration (oscillation) in ropes and springs and by experiments using water waves
P3.1.3Describe the features of a wave in terms of wavelength, frequency, crest (peak), trough, amplitude and wave speed
P3.1.4
Describe how waves can undergo: (a). reflection at a plane surface:
- (b) .refraction due to a change of speed
P3.1.5Recall and use the equation for wave speed P3.2.1 Reflection of light
P3.1.6Know that for a transverse wave, the direction of vibration is at right angles to the direction of propagation and understand that electromagnetic radiation, water waves and seismic S-waves (secondary) are transverse
P3.1.7Know that for a longitudinal wave, the direction of vibration is parallel to the direction of propagation and understand that sound waves and seismic P-waves (primary) are longitudinal
P3.1.8Describe how waves undergo diffraction through a narrow gap
P3.1.9Describe how wavelength and gap size affects diffraction through a gap

2. Light

P3.2.1Use ray diagrams to define the terms normal, angle of incidence and angle of reflection
P3.2.1aDefine refraction as the change in direction of a light ray passing from one medium to another
P3.2.1bDescribe the action of a thin converging lens on a parallel beam of light and know that rays of light from an object at distance can be assumed to be parallel
P3.2.1cDescribe the dispersion of light as illustrated by the refraction of white light by a glass prism
P3.2.2Describe the formation of an optical image by a vertical plane mirror and give its characteristics compared with the object, i.e. same size, same distance from mirror, laterally inverted
P3.2.2aDefine and use the terms normal, angle of incidence and angle of refraction using ray diagrams
P3.2.2bDefine and use the terms principal axis, principal focus (focal point) and focal length
P3.2.2cKnow the seven colours (red, orange, yellow, green, blue, indigo, violet) of the visible spectrum in order of frequency and in order of wavelength
P3.2.3State that for reflection, the angle of incidence is equal to the angle of reflection; recall and use this relationship P3.2.2 Refraction of light
P3.2.3aDescribe the passage of light through a transparent material (limited to the boundaries between two media only)
P3.2.3bDraw and use ray diagrams for the formation of an image by a thin converging lens, limited to real images
P3.2.4Describe the formation of an optical image by a plane mirror and explain why it is virtual
P3.2.4aDescribe the characteristics of an image using the terms enlarged / same size / diminished and upright / inverted P3.2.4 Dispersion of light
P3.2.5Use simple diagrams, measurements and calculations for reflection by plane mirrors speeds of a wave in two different regions sin i sin r
P3.2.6Describe total internal reflection using ray diagrams
P3.2.7Define the critical angle as the angle of incidence at which the angle of refraction is 90° and above which all light is totally internally reflected
P3.2.8Describe total internal reflection in optical fibres and state some common applications of optical fibres of a virtual image by a thin converging lens using the terms real / virtual magnifying glass

3. Electromagnetic spectrum

P3.3.1Know the main regions of the electromagnetic spectrum (radio, microwave, infrared, visible, ultraviolet, X-ray, gamma) in order of frequency and in order of wavelength
P3.3.2Know that all electromagnetic waves travel at the same high speed in a vacuum
P3.3.3
Know some applications of the different regions of the electromagnetic spectrum including: transmissions, radar (cell) phone, microwave ovens thermal imaging scanners treatment:
- (a) . radio waves; radio and television
- (b) .microwaves; satellite television, mobile
- (c) . infrared; remote controllers for televisions,
- (d) .visible light; vision, photography
- (e) . ultraviolet; detecting fake bank notes
- (f) . X-rays; medical scanning, security
- (g) .gamma rays; detection of cancer and its
P3.3.4
Describe the harmful effects on people of excessive exposure to electromagnetic radiation, including: eyes, leading to skin cancer and eye conditions damage to cells in the body:
- (a) . ultraviolet; damage to surface cells and
- (b) .X-rays and gamma rays; mutation or
P3.3.5Know that the speed of electromagnetic waves in a vacuum is 3.0 × 10 m / s and is approximately the same in air

4. Sound

P3.4.1Describe the production of sound by vibrating sources
P3.4.2State the approximate range of frequencies audible to humans as 20 Hz to 20 kHz
P3.4.3Know that a medium is needed to transmit sound waves
P3.4.4Determine the speed of sound in air using a method involving a measurement of distance and time
P3.4.5Describe how changes in amplitude and frequency affect the loudness and pitch of sound waves
P3.4.6Describe an echo as the reflection of a sound wave
P3.4.7Define ultrasound as sound with a frequency higher than 20 kHz
P3.4.8Describe the longitudinal nature of sound waves in air as a series of compressions and rarefactions
P3.4.9Describe, qualitatively, compressions as regions of higher pressure due to particles being closer together and rarefactions as regions of lower pressure due to particles being spread further apart
P3.4.10Know that, in general, sound travels faster in solids than in liquids and faster in liquids than in gases

4. Electricity and magnetism

1. Simple phenomena of magnetism

P4.1.1Describe the forces between magnetic poles and between magnets and magnetic materials, including the use of the terms north pole (N pole) and south pole (S pole), attraction and repulsion, magnetised and unmagnetised
P4.1.2State the differences between the properties of temporary magnets (made of soft iron) and the properties of permanent magnets (made of steel)
P4.1.3State the difference between magnetic and non-magnetic materials
P4.1.4Describe how a permanent magnet differs from an electromagnet
P4.1.5Describe a magnetic field as a region in which a magnetic pole experiences a force
P4.1.6State that the direction of a magnetic field at a point is the direction of the force on the N pole of a magnet at that point
P4.1.7Describe induced magnetism

2. Electrical quantities

P4.2.1State that there are positive and negative charges
P4.2.1aKnow that electric current is related to the flow of charge
P4.2.1bDescribe the voltage of the source as the cause of current in the circuit
P4.2.1cRecall and use the equation for resistance
P4.2.1dUnderstand that electric circuits transfer energy from a source of electrical energy, such as an electrical cell or mains supply, to the circuit components and then into the surroundings
P4.2.2State that positive charges repel other positive charges, negative charges repel other negative charges, but positive charges attract negative charges
P4.2.2aKnow that electric current in metals is related to the flow of electrons
P4.2.2bKnow that the voltage of the source is shared between the components in a series circuit
P4.2.2cDescribe an experiment to determine resistance using a voltmeter and an ammeter and do the appropriate calculations P4.2.5 Electrical energy and electrical power
P4.2.2dRecall and use the equation for electrical power
P4.2.3Describe electrostatic charging by friction, and simple methods to determine if an object is charged
P4.2.3aDescribe the use of ammeters (analogue and digital) with different ranges
P4.2.3bDescribe the use of voltmeters (analogue and digital) with different ranges
P4.2.3cRecall and use the equation for electrical energy E = I Vt
P4.2.3dSketch and explain the current–voltage graph of a resistor of constant resistance
P4.2.4Know that charging of solids by friction involves only a transfer of negative charge (electrons)
P4.2.4aKnow the difference between direct current (d.c.) and alternating current (a.c.) P4.2.3 Voltage (electromotive force and potential difference)
P4.2.4bDefine the kilowatt-hour (kW h) and calculate the cost of using electrical appliances where the energy unit is the kW h P4.3.1 Circuit diagrams and circuit components
P4.2.4cRecall and use the following relationship for a metallic electrical conductor: (a). resistance is directly proportional to length (b). resistance is inversely proportional to cross-sectional area
P4.2.5Distinguish between electrical conductors and insulators and give typical examples P4.2.2 Electric current
P4.2.6State that charge is measured in coulombs
P4.2.7Describe an electric field as a region in which an electric charge experiences a force
P4.2.8State that the direction of an electric field at a point is the direction of the force on a positive charge at that point a point per unit time; recall and use the equation in terms of the movement of delocalised (mobile) electrons positive to negative and that the flow of electrons is from negative to positive electrical work done by a source in moving a unit charge around a complete circuit done by a unit charge passing between two points in a circuit measured in volts (V)

3. Electrical circuits

P4.3.1Draw and interpret circuit diagrams containing cells, batteries, power supplies, switches, resistors (fixed and variable), heaters, lamps, motors, ammeters, voltmeters and fuses, and know how these components behave in the circuit
P4.3.1aKnow that the current at every point in a series circuit is the same
P4.3.2Draw and interpret circuit diagrams containing generators and light-emitting diodes (LEDs), and know how these components behave in the circuit
P4.3.2aKnow how to construct and use series and parallel circuits
P4.3.3Calculate the combined resistance of two or more resistors in series
P4.3.4Know the advantages of connecting lamps in parallel in a circuit
P4.3.5Know that, for a parallel circuit, the current from the source is larger than the current in each branch
P4.3.6Know that the combined resistance of two resistors in parallel is less than that of either resistor by itself
P4.3.7
Recall and use in calculations, the fact that: junction in a parallel circuit is equal to the sum of the currents that leave the junction a series circuit is equal to the sum of the individual p.d.s across each component arrangement of components is the p.d. across the whole arrangement:
- (a) . the sum of the currents entering a
- (b) .the total p.d. across the components in
- (c) . the p.d. across each branch of a parallel
P4.3.8Calculate the combined resistance of two resistors in parallel

4. Electrical safety

P4.4.1Describe the heating effect of current
P4.4.2
State the hazards of: extension leads, single and multiple sockets when using a mains supply:
- (a) . damaged insulation
- (b) .overheating cables
- (c) . damp conditions
- (d) .excess current from overloading of plugs,
P4.4.3Explain the use and operation of trip switches and fuses and choose appropriate fuse ratings and trip switch settings (knowledge of RCDs (Residual Current Devices) is not required)
P4.4.4Explain why the outer casing of an electrical appliance must be either non-conducting (double-insulated) or earthed

5. Electromagnetic effects

P4.5.1Know that a conductor moving across a magnetic field or a changing magnetic field linking with a conductor can induce an e.m.f. across the conductor
P4.5.1aDescribe a simple form of a.c. generator (rotating coil) and the use of slip rings and brushes where needed
P4.5.1bDescribe the pattern and direction of the magnetic field due to currents in straight wires and in solenoids
P4.5.1cKnow that a force acts on a current-carrying conductor in a magnetic field, including the effect of reversing: (a). the current (b). the direction of the field
P4.5.1dKnow that a current-carrying coil in a magnetic field may experience a turning effect and that the effect is increased by increasing: (a). the number of turns on the coil (b). the current (c). the strength of the magnetic field
P4.5.1eDescribe the construction of a basic transformer with a soft-iron core, as used for voltage transformations
P4.5.2State the factors affecting the magnitude of an induced e.m.f.
P4.5.2aSketch and interpret graphs of e.m.f. against time for simple a.c. generators
P4.5.2bDescribe the effect on the magnetic field around straight wires and solenoids of changing the magnitude and direction of the current
P4.5.2cRecall and use the relative directions of force, magnetic field and current
P4.5.2dDescribe the operation of an electric motor, including the action of a split-ring commutator and brushes
P4.5.2eUse the terms primary, secondary, step-up and step-down
P4.5.3Recall and use the equation where p and s refer to primary and secondary
P4.5.4Recall and use the equation for 100% efficiency in a transformer where p and s refer to primary and secondary
P4.5.5Describe the use of transformers in high- voltage transmission of electricity
P4.5.6Recall and use the equation to explain why power losses in cables are smaller when the voltage is greater

5. Nuclear physics

1. The nucleus

P5.1.1Describe the composition of the nucleus in terms of protons and neutrons
P5.1.2State the relative charges of protons, neutrons and electrons as +1, 0 and –1 respectively
P5.1.3Define the terms proton number (atomic number) Z and nucleon number (mass number) A and be able to calculate the number of neutrons in a nucleus
P5.1.4Use the nuclide notation X
P5.1.5State that an element may have more than one isotope and know that some isotopes are radioactive P5.2.1 Detection of radioactivity
P5.1.6Know the relationship between the proton number and the relative charge on a nucleus
P5.1.7Describe the processes of nuclear fission and nuclear fusion as the splitting and joining of nuclei

2. Radioactivity

P5.2.1Know what is meant by the terms ionising nuclear radiation and background radiation
P5.2.1aIdentify alpha ( α ), beta ( β ) and gamma ( γ ) emissions by recalling: (a). their nature (b). their relative ionising effects (c). their relative penetrating abilities ( β are not included, β -particles will be taken to refer to β ) P5.2.3 Radioactive decay
P5.2.1bKnow that radioactive decay is a change in an unstable nucleus that can result in the emission of α -particles or β -particles and / or γ -radiation and know that these changes are spontaneous and random
P5.2.1cDefine the half-life of a particular isotope as the time taken for half the nuclei of that isotope in any sample to decay; recall and use this definition in simple calculations, which might involve information in tables or decay curves (calculations will not include background radiation)
P5.2.1dKnow the following applications of radioactivity: (a). household fire (smoke) alarms (b). irradiating food to kill bacteria (c). sterilisation of equipment using gamma rays (d). measuring and controlling thicknesses of materials with the choice of radiations used linked to penetration and absorption (e). diagnosis and treatment of cancer using gamma rays
P5.2.2Know the sources that make a significant contribution to background radiation including: (a). radon gas (in the air) (b). rocks and buildings (c). food and drink (d). cosmic rays
P5.2.2aKnow that during α -decay or β -decay, the nucleus changes to that of a different element
P5.2.2bState the effects of ionising nuclear radiation on living things, including cell death, mutations and cancer
P5.2.3Know that ionising nuclear radiation can be measured using a detector connected to a counter
P5.2.3aKnow the change in the nucleus that occurs during β -emission: neutron → proton + electron P5.2.4 Half-life
P5.2.3bDescribe how radioactive materials are moved, used and stored in a safe way in terms of time, distance and shielding
P5.2.4Use count rate measured in counts / s or counts / minute
P5.2.4aUse decay equations, using nuclide notation, to show the emission of α -particles, β -particles and γ -radiation

6. Space physics

1. The Solar System

P6.1.1
Describe the Solar System as containing: order from the Sun dwarf planets such as Pluto and asteroids in the asteroid belt:
- (a) . one star, the Sun
- (b) .the eight named planets and know their
- (c) . minor planets that orbit the Sun, including
- (d) .moons, that orbit the planets

2. Stars and the Universe

P6.2.1Know that: (a). the Sun is the closest star to the Earth (b). astronomical distances can be measured in light-years, where one light-year is the distance travelled in (the vacuum of) space by light in one year
P6.2.1aKnow that stable stars are formed as protostars from interstellar clouds of gas and dust due to gravitational attraction
P6.2.1b
Know that: billions of stars the Milky Way are much further away from the Earth than the Sun is from the Earth:
- (a) . galaxies are each made up of many
- (b) .the Sun is a star in the galaxy known as
- (c) . other stars that make up the Milky Way
P6.2.2Calculate the time it takes light to travel a significant distance such as between objects in the Solar System
P6.2.2a
Know that the next stages of the life cycle of a star depend on its mass, limited to: as the Sun): red giant → white dwarf + planetary nebula supernova → neutron star supernova → black hole:
- (a) . a small mass star (about the same mass
- (b) .a large mass star: red supergiant →
- (c) . a very large mass star: red supergiant →
P6.2.2bKnow that the Milky Way is one of many billions of galaxies making up the Universe and that the diameter of the Milky Way is approximately 100 000 light-years
P6.2.3Know that the Sun contains most of the mass of the Solar System and this explains why the planets orbit the Sun
P6.2.3a
Know that the Big Bang Theory is supported by many astronomical observations and states that: point of high density and temperature years old:
- (a) . the Universe expanded from a single
- (b) .the Universe is still expanding
- (c) . the Universe is approximately 13.8 billion
P6.2.4Know that the force that keeps an object in orbit around the Sun is due to the gravitational attraction of the Sun
P6.2.5Know that the Sun is a star of medium size, consisting mostly of hydrogen and helium, and that it radiates most of its energy in the infrared, visible and ultraviolet regions of the electromagnetic spectrum P6.2.2 Life cycle of stars
P6.2.6Define orbital speed from the equation where r is the radius of the orbit and T is the orbital period; recall and use this equation
P6.2.7Know that the strength of the Sun’s gravitational field decreases and that the orbital speeds of the planets decrease as the distance from the Sun increases
P6.2.8Know that stars are powered by nuclear reactions that release energy and that in stable stars the nuclear reactions involve the fusion of hydrogen into helium form new stars with orbiting planets