Flashcards
PH1 Revision
Flashcards do conjunto (40)
- 1Describe conduction in metalsFree electrons gain kinetic energy
Transfer energy by colliding with other electrons - 2Describe conduction in non-metalsAtoms gain energy and vibrate faster
Atoms collide with other atoms and pass on their energy - 3Describe convectionParticles gain energy and spread out
Fluid becomes less dense and rises
Cooler denser fluid sinks - 4What is infrared radiation?Electromagnetic radiation emitted by hot objects
- 5What is meant by specific heat capacity?The energy needed to increase the temperature of 1kg of a material by 1 degree Celsius
- 6What is meant by U-value?How good a material is as an insulator. The lower the U-value the better the insulator.
- 7Explain how evaporation causes cooling.Particles with more energy
leave the surface of the liquid
lowering the average energy of the remaining particles
which lowers the temperature - 8Explain why condensation happens on cold windowsWater vapour transfers energy to the cooler glass
Particles move closer together and turn from a gas into a liquid - 9What does conservation of energy mean?Energy can't be created or destroyed, only changed from one form to another.
- 10What does high efficiency mean?A high proportion (or percentage) of the total energy is usefully transferred.
- 11How is a Sankey diagram used to calculate efficiency?The width of the useful arrow divided by the width of the total energy input.
- 12If one kWh costs 12 p and 5 kWh have been used, how much will the total cost be?60 p
- 13Give an advantage and a disadvantage of generating electricity using nuclear powerReliable
Radioactive waste - 14Give an advantage and a disadvantage of generating electricity using hydroelectric powerRenewable
Flooding valleys damages habitats - 15Give an advantage and a disadvantage of generating electricity using solar powerRenewable, no fuel cost
Unreliable - 16Give an advantage and a disadvantage of generating electricity using biofuelsCarbon neutral, renewable
Large areas of land needed to grow crops - 17What is meant by the 'frequency of a wave'?The number of waves passing a point each second.
- 18What is the unit of frequency?Hertz
- 19When is the Doppler effect observed?When a source of waves (light, sound or microwave) moves towards or away from an observer.
- 20What is a reflected sound wave called?An echo.
- 21Give two similarities between light and sound waves.Transfer energy
Can be reflected
Can be refracted
Can be diffracted - 22Give two differences between light and sound waves.Speed
Sound needs a medium to travel through (light does not)
Light has a shorter wavelength
Light has a higher frequency
Light is a transverse wave (sound is longitudinal) - 23What does transverse mean?Oscillations (or vibrations) are at 90 degrees to the direction of energy transfer
- 24What does longitudinal mean?Oscillations (or vibrations) parallel to the direction of energy transfer
- 25What does the red shift of light of distant galaxies provide evidence for?The expanding Universe and the Big Bang theory
- 26What is Cosmic Microwave Background Radiation?Electromagnetic radiation that is left over after the Big Bang that fills the Universe.
- 27What is the importance of Cosmic Microwave Background Radiation (CMBR)?The Big Bang theory predicts the existence of CMBR, no other theory does.
- 28If a source of wave moves towards you what happens to the speed, frequency and wavelength of the waves?Speed unchanged
Frequency is higher
Wavelength is shorter - 29If a source of wave moves away from you what happens to the speed, frequency and wavelength of the waves?Speed unchanged
Frequency is lower
Wavelength is longer - 30What is the Big Bang theory?A massive explosion from a single point that created the Universe
- 31What is the National Grid?Cables and transformers that connect power stations to consumers.
- 32What does a step-up transformer do?Increases the voltage
Decreases the current - 33What does a step-down transformer do?Decreases the voltage
Increases the current - 34How do transformers increase the efficiency of power transmission?A lower current in power cables, means less energy wasted heating the surroundings
- 35What stages are needed to generate electricity in a fossil fuel or nuclear fuel power station?Fuel used to boil water which turns to steam
Steam turns a turbine
Turbine turns a generator - 36What is the unit of Power?Watt
- 37What is the unit of specific heat capacity?J/kg⁰C
- 38If energy is measured in kWh, what are units of Power and time measured in?Power = kW
time = hours - 39If energy is measured in J, what are units of Power and time measured in?Power = W
time = s - 40What is the unit for wavelength?metres