EDEXCEL PHYSICS GCSE PAPER 1

• What are some sources of background radiation?

  -Radon gas is a radioactive gas made by rocks that naturally contain a small amount of uranium -Some food naturally contain small amounts of radioactive substances -Hospital treatments like x rays of gamma rays contribute to background radiation so people who work in hospitals often wear film badges called dosimeters to see how much they've been exposed to
• What happens to momentum in a collision?

  It is conserved
• What is the acceleration triangle?

  
• What four things could potentially happen to a wave when it hits a new interface ?

  It could be -refracted (wave passes through but changes direction)-reflected (waves bounces off)-transmitted (wave passes through material as normal) -absorbed (the wave disappears as the energy it stored is dissipated on the new material interface)
• What's the difference between vectors and scalars?

  Vectors have both size and direction, whereas scalars just have size.
• LIFE CYCLE OF MASSIVE STARS

  -RED SUPER GIANT, it expands and expands until eventualy it's core collapses forming a bounce back effect which causes a SUPER NOVA EXPLOSION. All that's left is the super dense core= neautron star. Gravity forms a black hole.
• What are the three different types of radiation?

  Alpha particles contain two protons and two neautrons, but no electrons so have a charge of +2. Beta particles are high speed, high energy electrons.They have a charge of -1 and form when a neutron transforms to a proton. Gamma rays are high frequency electromagnetic waves. They do not have an electrical charge.
• How do you calculate inertial mass?

  force on an object-------------------------acceleration
• What can x-rays be used for?

  x-rays can be used because they travel a lot further than visible light but are absorbed by bones in the body. This means they are useful for being used in medicine to make images of the inside of the bodyExcessive exposure may cause mutations in DNA
• What is the equation for work done?

  work done= force x distance
• What causes refraction?

  Refraction is caused by a change in speed. The greater the change in speed between two mediums (for example, light travels faster in air than it does in water or glass) the more the light will bend. If the light slows down, it will bend towards the normal (aka evening out).
• What is the order of the planets?

  Mecury Venus Earth Mars Jupiter Saturn Uranus Neptune
• How to calculate acceleration?

  v-u_______t
• What is Newton's 3rd Law?

  Every action has an equal and opposite reaction.
• What are some uses of infra sound and what is it?

  Infrasound is sound lower than 20 HzInfrasound can be sued to map out earthquake waves on Earth (seismic waves)
• What is radiation that is able to make atoms lose electrons?

  Ionising radiation
• What is the human detection noise range?

  20 Hz-20000 Hz
• What happens when waves pass through deep to shallow water?

  The waves will slow down at the interface of the shallow water and bend back towards the normal.
• How do you calculate stopping distance?

  Stopping distance= thinking distance+ breaking distance
• What are some examples of Renewable sources of energy?

  -Solar cells directly convert solar energy into electrical energy -hydroelectricity is formed when falling water it=s trapped in reservoirs. Can be stopped and started very quickly.-Tidal power is created when turbines turn as waves in a rive roll in and out with the tide. Not all places suitable for this, affects the wildlife living there.- Biofuels are made from waste wood/plants and are carbon neutral as they release the same amount of carbon dioxide they took out. However energy also needed to harvest the crops in the first place.
• What is work done and what is it measured in?

  Work done is the force taken to push an object over a distance It's measured in Joules The kinetic energy is the same as work done
• What is a free body diagram and what does it show?

  A free body diagram shows all the forces acting on a body. The body is depicted as a simple shape.For example gravity would be a downward facing arrow, and the normal is an upward facing arrow.Sizing of arrow is proportionate to size of force.
• How do you calculate the speed from a distance time graph?

  The speed is the gradient. So between two points on the graph, do the DIFFERENCE in the vertical axis reading divided by the DIFFERENCE in the horizontal axis reading.
• What do light and dark objects do with light waves?

  Lighter objects reflect more light waves Darker objects absorb more light waves
• What can radio waves be used for?

  Transmitting radio broad casts and general communicationSome are sent via satellites. Controllers on the ground can communicate with space craft using radio waves.
• What is the Steady State Theory and what is it's evidence?

  Suggests the universe is exanding but there was no original explosion. Matter is continuously being created as it expands. There isnt much evidence for this theory.
• What are some examples of vectors and scalars?

  Vectors= magnitude, displacement, acceleration, deceleration, forceScalars= temperature, time, length, mass
• What was the difference between the Plum Pudding model of the atom and Rutherford's Model of the atom?

  Due to research like passing alpha particles through various substances like gold foil, Rutherford suggested the atom had a small positive nucleus in the middle and the rest was empty space in which negative electrons were. So the idea of the nucleus was the difference.
• What is momentum given in?

  kgm/s
• What are some uses of Ultrasound and what is it?

  Ultrasound is sound higher than 20000 Hz-Sonar equipment (on a ship, see how deep sea is)-Baby scans (pulse send ultrasound pulse into womb, technology detects how long it took to echo)-can be used to clean things using pressure
• How can the change in GPE of an object be calculated?

  Change in GPE = mass x gravitational field strength x change in vertical height
• What can gamma rays be used for?

  Can transfer a lot of energy and can kill cells so are useful to sterilise surgical instruments and food by killing potentially harmful microorganisms.Can kill cancer cells in radiotherapy. Can also be used to detect cancers.Excessive exposure may cause mutations in DNA
• Energy is measured in?

  Joules (j)
• What does a converging lens do and what is a use for it?

  Converging lenses are fat glass lenses that cause parallel light rays to converge (come together at a focal point) this creates a virtual image which cannot be projected that is inverted. A magnifying glass is a converging lens.
• What is the difference between transverse waves and longitudinal waves?

  Transverse waves travel up and down at a constant rate like the first image. They have an amplitude and wave length. LIGHT and RADIO waves are transverse. Longitudinal waves have a compression where the particles become very close together, then spread out again. The energy travels in the direction of the compressions. Sound is an example of a longitudinal wave.

  
• What controls fission?

  Feul rods slow down the neutrons to increase the chance they have of being absorbed by a uranium-235. Feul rods are inserted into a moderator. The chain reaction is also controlled using control rods which contain elements which absorb neutrons. These are placed between the feul rods in the reactor core.
• What are the disadvantages of fossil fuels?

  Fossil fuels are non renewable. This means the store of them, as it's being used more and more, will eventually run out (for example our oil deposits will have run out by 2052). Fossil fuels also release carbon dioxide into the environment, which contributes to climate change.
• What is red-shift?

  Our sun contains helium which creates black lines on the spectrum of light where light has been absorbed.. Red shift is when the pattern of blakc lines has been moved towards the red end of visible colour. The further a star is away from us, the more it is red-shifted. Red-shift csn used for evidencd of a generally expanding universe.
• What is the relationship between mass and acceleration?

  Inversely proportional
• How do you calculate momentum?

  Momentum= mass x velocity