PAST PAPER Q'S

• Transformers are used to increase the voltage output of power stations before distribution via the National Grid.

  Explain why electricity is transmitted at high voltages.

  when a current flows through a wire it causes it to heat up

  increasing the output voltage reduces the output current

  minimising the energy lost as heat
• State the input voltage to the transformer from the mains supply.

  230 V
• Explain why the output power is less than the input power.

  the transformer is not 100% efficient

  when a current flows through the transformer wires, it causes them to heat up

  energy is lost to the surroundings
• Draw a labelled diagram of a transformer.

  
• Explain how a transformer works to increase the voltage of an alternating current input.

  - AC sets up an alternating magnetic field in the primary coil

  alternating magnetic field is induced in the core

  - iron core strengthens magnetic field

  - alternating magnetic field at the secondary coil

  - induces an alternating current at the secondary coil

  - step up transformer if the secondary coil has more turns than the primary coil
• Give an example of a transverse wave.

  Water ripples or any electromagnetic wave
• State the equation linking time period and frequency.

  time period = 1 ÷ frequency
• name a non - contact force

  electrostatic
• how do stars become black dwarfs

  only stars smaller as the sun become black dwarfs
• when scientists observe the light from distant galaxies they observe an increase in ______ of light from those galaxies

  WAVELENGTH
• How does the Big bang theory describe the inverse when it began

  very dense and extremely hot
• Describe the life cycle of stars much more massive than the sun including information about new elements

  NEBULA is a large cloud of dust and gas, this dust and gas is pulled together by attraction of gravity's causing increase in temperature to start fusion process to form protostar.

  
  

  fusion produces new elements

  
  

  the star expands to become a super giant the star collapses rapidly and explodes called a supernova creating elements heavier than iron and distributing them throughout the universe. leaving behind black hole/neutron starSee an expert-written answer!We have an expert-written solution to this problem!
• what property of a star does a range of wavelength depend on

  temperature
• what force causes planets to orbit the sun

  gravity

  OR

  gravitational force
• how are planets and moons similar

  their orbit is circular
• strength

  weakness

  S - as the balloon expands the dots get further apart representing the galaxies moving apart

  
  

  W - dots are only on the surface of the balloon galaxies are throughout the universe

  
• Most scientists now believe that Theory 2 is correct.

  Suggest what is likely to have caused scientists to start thinking Theory 1 is wrong.

  new evidenceSee an expert-written answer!We have an expert-written solution to this problem!
• explain why the star is stable while it is in the main sequence stage of its life cycle

  gravitational force inwards and fore as result of fusion reaction outwards are balanced
• Describe what will happen to the star between the main sequence stage and the end of the stars life cycle

  expand to become a red giant

  star will collapse to become white dwarf

  cools to become a black dwarf
• suggestion that the universe began from a very small region

  the furthest galaxies are moving the fastest

  this suggests the universe is expanding from a very small region
• New observations and data that do not fit existing theories should undergo peer review give one reason why this is important


  detect false claims

  detect biasSee an expert-written answer!We have an expert-written solution to this problem!
• The andromeda galaxy is moving towards the earth

  describe how the wavelength and frequency of the light from Andromeda seem to have changed when viewed from the earth

  wavelength seems to have decreases

  frequency increasedSee an expert-written answer!We have an expert-written solution to this problem!
• Explain why the velocity of the satellite changes as it orbits the earth

  force of gravity causes the satellite to accelerate toward the earth

  the acceleration causes a change in direction

  velocity changes because direction changes
• what makes microwaves suitable for sending communications to a satellite in space

  can travel through atmosphere
• When a radio wave are absorbed by an aerial they may create an alternating current in a electrical circuit if an AC is created what frequency would it have


  expansion due to fusion energy
• Describe what will happen to the sun between it leaving the main sequence group and becoming a white dwarf

  sun frogs from main sequence star to red giant then fro red Giant to white dwarf.

  
  

  when the sun changes to a red giant the surface temp will decrease

  
  

  when I changes from red giant to white dwarf the surface temp will increase
• Explain how current is induced in the wire

  in terms of space physics


  as the wire moves through the earths magnetic field

  a pd is induced between the end of the wire

  the wire must be parr of a complete circuit
• when observed from the earth there is an increase in wavelength of light from distant galaxies what is this called

  red shift
• explain how this observation support the Big Bang theory of the formation of the universe

  the furthest galaxies shoe the biggest red shift

  meaning that the furthest galaxies are moving fastest

  so universe is expanding
• state one other piece of evidence that support the Big Bang theory if the formation of the universe

  CMBR
• WHY are telescopes that detect different types of electromagnetic waves used to observe the universe

  different types of electromagnetic waves
• what is red shift

  light moves to red end of spectrum

  and galaxy move away from the earth
• what does the measurement of its red shift tell scientists about the star

  it is the star furthest from the earth

  moving sway fastest
• describe the Big Bang theory

  all matter compressed ro start at single point

  massive explosion sends matter outwards
• explain why scientists that the solar system was formed form the material produced when earlier stars exploded

  solar system contains heavy elements these heavy elements are formed by fusion in super nova
• the light arriving from distant galaxies provides scientists with evidence to support the Big Bang theory


  light shows a reds shift

  galaxies moving away from the earth
• state difference between ultraviolet and visible light waves

  U - is higher freq

  U - shorter wavelength
• what does red shift tell scientists about the direction most galaxies are moving

  away from each other
• to stay in its present orbit around the earth each satellite must move at a particular

  speed
• Explain how stars like the sun were formed

  from giant cloud of gas or hydrogen pulled into a smaller volume by gravity