[Everything You Need To Know]

All objects emit and absorb infrared radiation Hotter object = more infrared radiation emitted

Dark, matt surfaces = better emitters + absorbers of infrared radiation

Light, shiny surfaces = poor emitters + absorbers + Good reflectors

50 oC 100 oC

- The particles of solids, liquids and gases have different amounts of energy.

- Solid = Strong forces of attraction, particles close together, fixed regular arrangement, vibrate with neighbouring particles in fixed position.

- Liquid = Weak force of attraction, particles close together(can move past each other), irregular arrangement, move randomly + slowly

- Gas = No forces of attraction, particles have more energy than solid + liquid, free to move, move randomly + quickly.

- Transfer of energy by: conduction, convection, evaporation and condensation all involves particles

- Condensation = losing kinetic energy, particles closer together, gas - liquid, water vapour in air becomes liquid when is contact with a cold surface.

- Evaporation = particles escape liquid, particles can evaporate below water’s boiling point, particles near surface break force of attraction and become gas, hotter particles escape, leaving the liquid at a lower temperature.

- Rate of transfer = surface area & volume, material, colour.

- The larger the temperature difference to quicker the rate of heat transfer.

This can come up as 6 marker!

- Specific heat capacity = J/Kg°C- E = m x c x θ- E is energy transferred in joules (J)- m is mass in kilograms (kg) - θ is temperature change in degrees Celsius, (°C) - c is specific heat capacity in J / kg °C

- Water may be stored in solar panels so it may be used for domestic hot water.

- The lower the U-value, the better the material is as an insulator.- U-values measure how effective a material is as an insulator.

1. 3.

2.

4.

1. how effective a material is as an insulator

2. (the U-value) decreases

3. 4200, allow 2 marks for correct substitution ie 6930 = 0.330 x c x 5.0 answers of 1050 or 840 (3 marks), 1 mark for units ( j/kg oC)

4. (air) particles spread out (which causes the) air to become less dense/ expand (so the) warm air rises

- Energy can be transferred usefully, stored, or dissipated, but cannot be created or destroyed.

- When energy is transferred only part of it may be usefully transferred, the rest is ‘wasted’

- Wasted energy is eventually transferred to the surroundings, as thermal energy, (surroundings become warmer. Spreads out and becomes less useful.

- To calculate the efficiency of a device use: - efficiency = useful energy out

total energy in X (100%)- efficiency = useful power out

total power in X (100%)

Leaf blower 3.

1.

2.

1. warms it

2. 37.5% or 0.375

3. 5.88 (watts)

N - NuclearE - Electrical (mains)G - Gravitational Potential(pen on tableL - Light (bulb)E - Elastic Potential ( spring)C - Chemical (batteries)T - Thermal (fire)S - Sound (speakers)---K - Kinetic

- E = P x t == Energy transfer from mainsE = Joules (energy)P = Watts (power)T = seconds (time)

- To calculate the cost of mains electricity given the cost per kilowatt-hour.

- E.g Electricity = 15p per KwhPower = 5000watts per hour from kettleRuns for 30 minsCost?

5000watts = 5Kwh5Kw x 0.5hr (30 mins) = 2.5Kwh2.5Kwh x 15p = 37.5p

- Payback time = cost / saving per year(or month depending)

1. Chemical, kinetic, sound

2. Examples of relevant statements:• energy efficient boiler saves the most (energy / money) per year• loft insulation costs the least to install• double-glazing costs the most to installExamples of statements that include cost effectiveness • loft insulation is the most cost effective in the long term • double-glazing is the least cost effective• loft insulation has the shortest payback time • double-glazing has the longest payback time • payback time calculated for any method Examples of further detail • for cost effectiveness install in the following order: loft, cavity wall, boiler, double-glazing • for reducing energy use install in the following order: boiler, loft, cavity wall, double glazing• don’t install double-glazing for insulation purposes • double-glazing won’t pay for itself in your lifetime • justified choice of best / worst method

- Power stations need an energy source to heat up water, these are the ones you need to know:

- Burning fossil fuels heats water- Uranium and plutonium, when energy from nuclear fission

heats water- Burning biofuels heats water- Water and wind can be used to rotate turbines- Electricity can be generated directly from sunlight- Geothermal energy is when steam from volcanic areas is used

to turn turbines- Hydroelectricity in remote areas(country-side) and solar cells

for roadside signs

- Generating electricity has some effects:- The release of substances into the atmosphere - The production of waste materials- Noise and visual pollution - The destruction of wildlife habitats.

- Electricity is distributed from power stations to consumers (us) along the National Grid.

- Step-up transformer Increases voltage and decreases Current, this reduces energy loss(as thermal energy) which makes it more efficient.

This can come up as 6 marker!

Why is a Step-up transformer used in the national grid? [3 marks]

1. 5.

2.

3.

4.

1. (heated) water turns to steam, steam turns a turbine, turbine turns a generator

2. advantage any one from: • produce no / little greenhouse gases / carbon dioxide • high(er) energy density in fuel

• long(er) operating life disadvantage any one from: • produce (long term) radioactive waste

• accidents at nuclear power stations may have far reaching or long term consequences

• high(er) decommissioning costs• long(er) startup time

3. any one from: • cannot be seen • no hazard to (low flying) aircraft / helicopters • unlikely to be or not damaged / affected by (severe) weather • (normally) no / reduced shock hazard

4. They rely on the wind 5. Increases voltage

Decreases currentReduce power loss(heat)Increase efficiency

- Waves transfer energy

- Waves may be either transverse or longitudinal.

- Electromagnetic waves are transverse, soundwaves are longitudinal and mechanical waves maybe either transverse or longitudinal

- All types of electromagnetic waves travel at the same speed through a vacuum (space).

- Electromagnetic waves make up a continuous spectrum

- Longitudinal waves show areas of compression and rarefaction.

- Waves can be reflected, refracted and diffracted (Learn the names of the angles below or look next slide)

- Waves undergo a change of direction when they are refracted at an interface

- You must know the terms frequency, wavelength and amplitude

- All waves obey the wave equation: V = f x λ

v = speed in metres per second, m/s

f = frequency in hertz, Hz

λ = wavelength in metres, m

- Radio waves, microwaves, infrared and visible light can be used for communication.

- The normal is a construction line perpendicular to the reflecting surface at the point of incidence.

- The angle of incidence = the angle of reflection.

- The image produced in a plane mirror is virtual and upright

- Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound.

- The pitch of a sound is determined by its frequency and loudness by its amplitude

- Echoes are reflections of sounds.

- If a wave (e.g light) is moving away from you, the observed wavelength increases and frequency decreases.

- If a wave (e.g light) is moving towards you, the observed wavelength decreases and frequency increase

- This is known as the Doppler effect

- Observed wavelength (of light) are increases from distant galaxies, the further away the galaxies are the faster they are moving and a bigger increase in wavelength- Red-Shift.

- Red-shift shows all galaxies are moving away from us, this supports the big bang as everything must have started at 1 point.

- Cosmic microwave background radiation (CMBR) is radiation from the beginning of the universe.

- The ‘Big Bang’ theory is currently the only theory that can explain the existence of CMBR.

5.

1.

2.

3.

4.

1. Microwave 4. Doppler effect

2. Refraction

3. any two from: • transverse • same speed (through air) • can be reflected• can be refracted • can be diffracted ... more

5. 0.773 (metres)allow 1 mark for correct substitution ie 340 = 440 × λallow 2 marks for an answer that rounds to 0.773

1. A vacuum flask is designed to reduce the rate of energy transfer by heating process. Describe how the design of a vacuum flask keeps the liquid inside hot?

2. A car engine that overheats can be damaged or even catch fire. Therefore a cooling system transfers energy from the engine to a radiator. The energy in the radiator is transferred to the air. Explain the factors that affect the rate of energy transfer in the engine and radiator.

3. Home heating bills can be very expensive. Describe the different methods by which we can reduce the rate of energy transfer at home and reduce the home heating bills.

4. Compare the similarities and differences between the process of conduction in metals and nonmetals.

5. Explain why an electric heater is the only appliance that can possibly be 100% efficient.

6. Compare the advantages and disadvantages of buying compact fluorescent bulbs rather than filament bulbs

7. Advantages and disadvantages of the different methods of energy production

8. Power stations that burn fossil fuels produce waste gases that can cause pollution. Describe the effect that these gases could have on the environment and what could be done to reduce the amount of these gases emitted by power stations.

9. What are the advantages and disadvantages of using solar energy to heat water in a tank rather than using an electric immersion heater?

10. Advantages and disadvantages of overhead and underground cables.

11. Compare the advantages and disadvantages of overhead power lines and underground cables in the transport of electrical energy around the country

12. The diagram shows an oscilloscope trace of the sound wave produced by a musical instrument.

Explain, in detail, how the waveform would change if the instrument produced a sound which was louder and at a higher pitch

13. One theory suggests the universe began with the Big Bang. Explain what is meant by the Big Bang and describe the evidence that supports this theory

14. Explain how red-shift provides evidence for the Big Bang theory.