physics. paper 1

• What is a system?


  An object or group of objects
• What is work done?

  energy transferred
• Name all the energy stores

  Thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear
• What is the law of conservation of energy?

  Energy cannot be created or destroyed, only transferred
• What is dissipated energy?

  wasted energy
• What does friction cause?

  energy to be transferred to thermal energy
• how can we reduce friction?

  lubricants
• what is mechanical work done?

  using force to move an object
• what is electrical work done?

  a current transferring energy
• what is conduction?


  The process where vibrating particles transfer energy to neighbouring particles
• What is convection?


  Where energetic particles move away from hotter to cooler regions
• How does conduction happen?

  The collisions transfer kenetic energy making the neighbouring particles vibrate and collide with their neighbours. The process repeats and energy is passed along the object until heat is spread out evenly.
• How does convection work?

  As a fluid is heated, particles at the bottom lose density and rise. They cool and sink when they reach the top, and are replace by newly heated, rising particles. This cycle continues until the fluid reaches a constant temperature, when it stops. This is a convection current.
• how can you prevent energy loss in homes?

  thermal insulation

  -cavity walls(air gap reduces amount of energy transferred by conduction)

  -cavity walls full of insulated foam

  -double glazed windows

  -loft insulation(fibreglass layer)

  - thick curtains
• What are non-renewable energy resources?

  -Coal

  -Oil

  -Natural Gas

  -Nuclear fuels
• What are renewable energy sources?

  solar, wind, water waves, hydro-electricity, bio-fuel, tides, geothermal
• what are the two things energy resources are used for?

  transport and domestic uses
• what are some domestic uses of energy resources?

  cooking/heating- natural gas and coal

  solar water heaters/burning bio-fuel
• How are renewable and non-renewable energy resources used for transport?

  steam trains-coal

  petrol/diesel-oil

  electric cars-bio-fuel
• what are disadvantages of wind turbines and solar cells?

  -high upront cost

  -making process produces pollutants

  -dependant on weather

  -no way to increase supply in peak demand

  -take lots of space as just one doesnt produce a lot of electricity
• what are advantages of wind turbines and solar cells?

  -low running costs

  -renewable

  -cheaper every year

  -no pollution

  -dont damage environment
• where does most of the heat energy for geothermal power come from?

  slow decay of various radioactive elements like uranium
• what are advantages of geothermal power?

  - Renewable

  - No production of polluting gases

  - Free energy resource

  - reliable over long periods
• what are disadvantages of geothermal power?

  expensive power plants compared to the amount of energy it produces, limited locations.
• How does hydroelectric power work?

  water behind dams flood through turbines which turns generators
• what are advantages of using hydro-electricity?

  -large amounts of energy with no pollution

  -provide immediate repsonse to increased demand

  -running costs fairly low

  -reliable
• what are disadvantages of using hydro-electricity?

  -often flood huge areas

  -may stop boats and fish from travelling, affects their migration

  -set up expensive

  -loss of habitat for some species
• what are the advantages of tidal barrages?

  -no pollution

  -reliable

  -no fuel costs

  -minimal running costs

  -excellent for storing energy ready for periods of peak demand
• what are the disadvantages of tidal barrages?

  -stop boats and fish from travelling

  -loss of habitat

  -provide significantly less energy than the bigger 'spring' tides

  -don't work when water level is the same either side of the barrage

  -initial costs are moderately high
• what are advantages of wave power?

  -no pollution

  -very useful on small islands

  -no fuel costs

  -minimal running costs
• what are disadvantages of wave power?

  -fairly unreliable (waves tend to die out when the wind drops)

  -never likely to provide energy on large scale

  -initial costs are high

  -disturbs seabed and and habitats of marine animals

  -hazard to boats
• what are advantages of using bio-fuel?

  -carbon neutral

  -fairly reliable (crops take short time to grow)

  -easy to transport

  -renewable
• what are disadvantages os using bio-fuel?

  -cant respond to immediate energy demands

  -cost to refine is high

  -take up lots of space, so might not be enough space for crops grown for food

  -large areas of forests have been cleared, loss of habitat

  -deay and burning increases co2 and methane emissions
• what are advantages of non-renewable energy resources?

  -enought to meet current demand

  -reliable

  -low running costs
• what are disadvantages of non-renewable energy resources?

  -huge amount of co2, global warming

  -will run out

  -burning coal and oil releases sulfur dioxide, acid rain term-46harmful to trees and soil

  -nuclear waste is dangerous and dificult to dispose

  -cost of nuclear power is high, cost of power plant and decommissioning
• What is specific heat capacity?

  The amount of energy required to increase the temperature of 1kg of a substance by 1 degree celcius
• How does burning oil and coal harm the environment?

  it releases sulfur dioxide which causes acid rain which harms trees and soil
• Why is renewable energy use growing?

  There is increasing concern over the environmental impacts of fossil fuel combustion.
• why are energy providers reluctant to build new renewable power plants?

  cost is high
• how do you calculate the charge flow?

  charge flow (C) = current (A) x time (s)