Physics Paper 1

• What is a system?


  An object or a group of objects
• What happens when a system changes?

  The way energy is stored also changes
• What happens when energy is transferred into an object?


  The energy is stored in one of the objects energy stores
• What are the different energy stores?

  • Thermal
  • Kinetic
  • Gravitational potential
  • Elastic potential
  • Chemical
  • Magnetic
  • Electrostatic
  • Nuclear
• What are the different ways in which energy is transferred?

  • Mechanically
  • Electrically
  • Thermally
  • Radiation
  • Light
• What are closed systems?


  Systems where energy cannot enter or leave
• What is the net change of energy in a closed system?


  It is always 0
• What is an example of how energy is transferred by heating?

  • Water is the system (object)
  • Energy is transferred to the water by heating
  • The heat enters the water's thermal energy store
  • This causes the temperature to rise
• What is work done?


  Another way of saying energy is transferred
• When is work done?


  When current flows against resistance in a circuit or by a force moving an object
• What is an example of work being done?

  The energy exerted by a person to throw a ball upwards
• How do you calculate Kinetic energy?


  Kinetic energy = 0.5 x mass x (speed)²
• How do you calculate Elastic potential energy?


  Elastic potential energy = 0.5 x spring constant x (extension)²
• How do you calculate Gravitational potential energy?


  Gravitational potential energy = mass x gravitational field strength x height above the surface
• How do you calculate Specific heat capacity?


  heat energy = mass x specific heat capacity x temperature change
• How do you calculate Power?


  Power = work ÷ time
• What is the conservation of energy principle?


  Energy can be transferred but is never created or destroyed
• What is another name for dissipated energy?


  Wasted energy
• What is dissipated energy?

  Energy that is lost or wasted during an energy transfer
• What is conduction?


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


  The process where energetic particles move from hotter to cooler regions
• Where does convection happen?

  Convection only happens in gases and liquids
• How can we reduce energy waste?

  • Lubrication
  • Thermal insulation
• How do we reduce energy waste through lubrication?

  • putting oil in a motor
  • this reduces friction so that less energy is lost as heat with friction
• How do we reduce energy waste through thermal insulation?

  • double glazing windows
  • so less thermal energy is lost
• What is efficiency?


  The ratio of useful work done to the energy supplied to it
• How do you calculate Efficiency?

  • Efficiency = useful output energy transfer ÷ total input energy transfer
  • Efficiency = useful power output ÷ total power input
• How can the efficiency of a system be increased?

  By reducing waste output
• What are the main non-renewable energy sources?

  • Fossil fuels (coal, oil, gas)
  • Nuclear fuel
• What is renewable energy?

  Energy that can be replenished as it's used
• What is non-renewable energy?

  Energy sources that can't be replenished
• What are the main energy uses?

  • Transport
  • Electricity
  • Heating
• What is needed for charge to flow?

  • Circuit must be closed
  • There must be a source of potential difference
• What is current?


  The flow of electrical charge
• How do you calculate potential difference?


  Potential difference = current x resistance
• How does resistance change?

  • Current
  • Temperature
  • Length
  • Light
  • Voltage
• How does resistance change with current?

  • As current increases, electrons have more energy
  • They collide with other atoms in the resistor
  • This makes them vibrate
  • Resistance increases and current decreases
• How does resistance change with light?

  The greater the intensity of light, the lower the resistance
• What are the properties of a Series circuit?

  • Closed circuit
  • Current follows a single path
  • Current is the same throughout
• What are the properties of a Parallel circuit?

  • Branched circuit
  • Current splits
  • Potential difference the same throughout