2.18 know that the voltage across two components connected in parallel is the same
VT = V1 = V2
2.19 calculate the currents, voltages and resistances of two resistive components connected in a series circuit
VT = V1 + V2
IT = I1 = I2
RT = R1 + R2
2.21 know and use the relationship between energy transferred, charge and voltage: E = Q × V
Energy Transferred (J) = charge (C) x Voltage (V)
2.22 identify common materials which are electrical conductors or insulators, including metals and plastics
Conducting Materials:
- Copper
- Aluminium
- Gold
- Silver
Will conduct electricity
Insulating Materials:
- Glass
- Air
- Plastic
- Rubber
- Wood
Will not conduct electricity
2.23 practical: investigate how insulating materials can be charged by friction
- Hold polythene rod and cloth next to up small pieces of paper one at a time, observe.
- Now rub the rod with the cloth
- Again hold close to small pieces of paper, observe.
- Turn on a tap so a thin stream of water is flowing
- Hold the rod about 1cm away from the water just below the nozzle, observe
- Repeat with different material rods and cloths
2.28 explain some uses of electrostatic charges, e.g. in photocopiers and inkjet printers
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Paper is charged negatively in certain regions. Then positively charged paint droplets are sprayed onto the paper and attracted to the negative regions of the paper giving the desired image. |
3.01 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s) and second (s)
the units for:
angle = degree (°)
frequency = hertz (Hz)
wavelength = metre (m)
velocity = metre/second (m/s)
time = second (s)
3.02 explain the difference between longitudinal and transverse waves
Transverse Waves:
- A wave that vibrates or oscillates at right angles (perpendicular) to the direction in which energy is transferred/ the wave is moving.
- g. Light
Longitudinal Waves:
- A wave that vibrates or oscillates at parallel to (along) the direction in which energy is transferred/ the wave is moving.
- g. Sound
3.03 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave
Key Definitions:
- Wavefront: Created by overlapping lots of different waves. A wavefront is where all the vibrations are in phase and the same distance from the source.
- Amplitude: The maximum displacement of particles from their equilibrium position.
- Wavelength: The distance between a particular point on one cycle of the wave and the same point on the next cycle.
- Frequency: The number of waves passing a particular point per second. Is measured in Hertz (Hz).
- Time Period: The time it takes for one complete wave to pass a particular point.
3.04 know that waves transfer energy and information without transferring matter
Waves can transfer energy and information with out transferring matter, for example sun light, it transfers energy as it makes the earth warm without bringing any matter.
3.05 know and use the relationship between the speed, frequency and wavelength of a wave: v = f × λ
wave speed (m/s) = frequency (Hz) x Wavelength (m)
3.06 use the relationship between frequency and time period: time period x frequency = 1 or f = 1/T
Frequency (Hz) = 1/ Time Period (s)
3.07 use the above relationships in different contexts including sound waves and electromagnetic waves
You will need to use any of the in 3.05 and 3.06 to solve problems to do with sound waves and electromagnetic (light) waves
3.08 explain why there is a change in the observed frequency and wavelength of a wave when its source is moving relative to an observer, and that this is known as the Doppler effect
Doppler Effect:
- When a car is not moving and its horn sounds, the sound waves we receive are a series of evenly spaced wavefronts.
- If a car is moving, wavefronts of the sound are no longer evenly spaced.
- Ahead of the car wavefronts are compressed as the car is moving in the same direction as the wavefronts. This creates a shorter wavelength and a higher frequency.
- Behind the car wavefronts are more spread out as the car is moving away from the previous wavefronts. This creates a longer wavelength and a lower frequency.
3.10 know that light is part of a continuous electromagnetic spectrum that includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space
Electromagnetic Spectrum:
- A continuous spectrum of waves of differing frequency.
- All electromagnetic waves have the following properties:
- Transfer energy
- Are transverse waves
- Travel at the speed of light in a vacuum
- Can be reflected and refracted
3.11 know the order of the electromagnetic spectrum in terms of decreasing wavelength and increasing frequency, including the colours of the visible spectrum
Radio Waves
Microwaves
Infrared (IR)
Visible Light
Ultraviolet (UV)
X – Rays
Gamma Rays
these are written in order of increasing frequency, lowest at the top
and decreasing wavelength, lowest at the bottom.
the colours displayed are in order of lowest frequency to the left highest frequency to the right.
3.12 Explain some of the uses of electromagnetic radiations, including: radio waves: broadcasting and communications, microwaves: cooking and satellite transmissions, infrared: heaters and night vision equipment, visible light: optical fibres and photography, ultraviolet: fluorescent lamps, x-rays: observing the internal structure of objects and materials, including for medical applications, gamma rays: sterilising food and medical equipment.
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uses of electromagnetic radiations, including: |
3.13 explain the detrimental effects of excessive exposure of the human body to electromagnetic waves, including: microwaves: internal heating of body tissue, infrared: skin burns, ultraviolet: damage to surface cells and blindness, gamma rays: cancer, mutation and describe simple protective measures against the risks
the detrimental effects of excessive exposure of the human body to electromagnetic waves:
• microwaves: internal heating of body tissue
• infrared: skin burns
• ultraviolet: damage to surface cells and blindness
• gamma rays: cancer, mutation
to reduce the risks:
- wear sun glasses, sun cream and stay in shade for UV
- Wear led clothing for Gamma
3.14 know that light waves are transverse waves and that they can be reflected and refracted
light is a transverse wave that can be reflected and refracted
3.17 practical: investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms
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1. Set up your apparatus as shown in the diagram using a rectangular block. 2. Shine the light ray through the glass block 3. Use crosses to mark the path of the ray. 4. Join up crosses with a ruler 5. Draw on a normal where the ray enters the glass block 6. Measure the angle of incidence and the angle of refraction and add these to your results table 7. Comment on how the speed of the light has changed as the light moves between the mediums. 8. Repeat this for different angles of incidence and different glass prisms. |
3.19 practical: investigate the refractive index of glass, using a glass block
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1. Set up your apparatus as shown in the diagram using a rectangular block. 2. Shine the light ray through the glass block 3. Use crosses to mark the path of the ray. 4. Join up crosses with a ruler 5. Draw on a normal where the ray enters the glass block 6. Measure the angle of incidence and the angle of refraction and add these to your results table 7. Calculate the refractive 8. Repeat steps 2 – 7 using 9. Find an average of your
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3.20 describe the role of total internal reflection in transmitting information along optical fibres and in prisms
Total Internal Reflection:
- Used to transmit signals along optical fibres.
3.21 explain the meaning of critical angle c
Critical Angle:
- The angle of incidence which produces an angle of refraction of 900 (refracted ray is along the boundary of the surface).
- When the angle of incidence is greater than the critical angle, total internal reflection occurs (all light is reflected at the boundary).
- This effect only occurs at a boundary from a high refractive index material to a low refractive index material.
3.22 know and use the relationship between critical angle and refractive index:
also remember:
critical angle = sin-1(1/n)
3.23 know that sound waves are longitudinal waves which can be reflected and refracted
sound waves are longitudinal waves which can be reflected and refracted.
3.24 know that the frequency range for human hearing is 20–20 000 Hz
the frequency range for human hearing is 20–20 000 Hz
3.26 understand how an oscilloscope and microphone can be used to display a sound wave
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With the microphone plugged into the oscilloscope and a sound incident on the microphone, the microphone will transfer the sound into an electrical signal which the oscilloscope can display .The x axis show the time base which can be adjusted for example 2ms for 1 square so time period and frequency can be calculated from this, along the y axis voltage is displayed as the wave is converted into an electrical signal this means amplitudes can be compared. |
3.28 understand how the pitch of a sound relates to the frequency of vibration of the source
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High frequency means high pitch. If a string vibrates with a higher frequency then the note sounds higher. |
3.29 understand how the loudness of a sound relates to the amplitude of vibration of the source
The greater the amplitude the louder the sound. Bigger vibrations of a sting mean more energy is being put in so more energy out as sound waves.
4.01 use the following units: kilogram (kg), joule (J), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s) and watt (W)
know the units for
Mass = kilogram (kg)
energy = joule (J)
velocity = metre/second (m/s)
acelleration = metre/ second 2 (m/s2)
force = newton (N)
time = second (s)
power = watt (W)
4.02 describe energy transfers involving energy stores: energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear and energy transfers: mechanically, electrically, by heating, by radiation (light and sound)
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Energy Stores: Chemical – e.g. the food we eat Kinetic – movement energy Gravitational – objects that are lifted up Elastic – e.g. from springs Thermal – from hot objects Magnetic – objects in magnetic fields Electrostatic – charged objects Nuclear – stored within a nucleus
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4.03 use the principle of conservation of energy
In any process energy is never created or destroyed. (It is just transferred from one store to another.)
4.05 describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of the above relationship, including their representation by Sankey diagrams
The energy flow is shown by arrows whose width is proportional to the amount of energy involved. The wasted and useful energy outputs are shown by different arrows.
4.06 describe how thermal energy transfer may take place by conduction, convection and radiation
Conduction is the transfer of thermal energy through a substance by the vibration of the atoms within the substance. Metals are good conductors because they have free electrons that can move easily through the metal, making the transfer of energy happen faster.
Convection occurs in a liquid or gas. These expand when heated because the particles move faster and take up more volume – the particles remain the same size but become further apart. The hot liquid or gas is less dense, so it rises into colder areas. The denser, colder liquid or gas falls into the warm areas. In this way, convection currents are set up which transfer heat from place to place.
Thermal radiation is the transfer of energy by infrared (IR) waves. These travel very quickly in straight lines.
4.08 explain how emission and absorption of radiation are related to surface and temperature
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– Light, shiny surfaces are good reflectors of IR and so are poor at absorbing it. – Dark, matt surfaces are poor reflectors and good at absorbing IR. – This means that placed next to a heat source, a dark object would heat up faster than a light one. – Dark matt surfaces are also best at emitting IR. This means that a hot object with a light shiny surface will emit less IR than a dark matt object at the same temperature. – Hotter objects emit more IR per second. The type of EM wave emitted also changes with temperature – the higher the temperature the higher the frequency of EM wave emitted. |
4.10 explain ways of reducing unwanted energy transfer, such as insulation
A good insulating material is a poor conductor that contains trapped air, e.g. foam, feathers, glass fibre. Being a poor conductor (non-metal) prevents heat transfer by conduction and the trapped air prevents convection currents.