Physics- waves

• How many nanometers are in a meter?


  1x10 to the power of 7
• Give the electromagnetic spectrum in order?


  Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.
• Which wave has the longest wave length?


  Radio waves.
• Which wave has the highest frequency?


  Gamma wave.
• name 3 types of errors that can occurs when doing an experiment?


  Systematic error, random error, and parallax error
• What property of a light wave changes when its refracted?


  velocity
• What is the first thing you should do when you see a maths question?


  convert all the units to the correct unit
• What happens in an electrical circuit when a car aerial absorbs radio waves?


  it causes electrons to oscillate with the same frequency as the radio wave
• Give two ways in which radio waves are different to sound waves?


  radio waves are transverse

  radio waves are electromagnetic
• Explain why a car had a maximum speed?


  there is a maximum forward force from the motor

  as the speed increases air resistance increases

  until air resistance is equal to the size of the forward force

  so the car can no longer accelerate
• What is the function of a microphone?


  to convert the sound waves into vibrations in current
• Why are x-rays used for medical imaging of bones?


  they can pass through soft tissue

  but are absorbed by bones so they can create an image of bone structures inside the body
• How do you get more precise results in an experiment?


  repeat measurements/ experiment
• Explain why refraction of waves happens between shallow and deep water?


  velocity of the wave is slower in shallow water

  so edge of wave front entering shallow water will slow down

  but the part of the wave in the deeper water remains a a high velocity
• What are waves?


  waves transfer energy but do not transfer matter. they are vibrations of matter or space
• What is an incident?


  a wave or energy that falls upon a surface
• What is thermal conductivity?


  rate of heat transfer through a material
• Method for infrared radiation practical?

  1. boil a kettle
  2. fill the Leslie cube with boiling water from a kettle
  3. aim the infrared detector at 1 side of the cube to record the temp of each different colour surface
  4. use the ruler to make sure the infrared detector is the same distance away from each surface
• What does Normal mean in physics?


  perpendicular to (at a right angle to)
• What is the law of reflection?


  The law of reflection states that the angle of incidence is equal to the angle of reflection. always obeyed by every individual ray
• What is specular reflection?


  produces and image e.g. A mirror
• What is diffuse reflection?


  does not produce an image
• What do diminished, undiminished and magnified mean in terms of images?


  Diminished means the image appears smaller, undiminished means the image appears the same size, and magnified means the image appears larger.
• What equipment is needed for the reflection and refraction experiment?


  light box, single slit slide, a normal created by a transparent semi-circular block
• Give the method for the reflection and refraction experiment?

  1. set up equipment with light box directed at the block
  2. draw around the semi-circular block
  3. mark the position of the light ray at the start, end and where it enters and exits the block
  4. remove the block and connect the marks to show the light rays
  5. add normal lines and measure the angles of incidence and refraction
  6. repeat on a new piece of paper for a range of angles of incidence
  7. repeat the experiment with blocks made of different transparent materials
• Give variables for reflection and refraction experiment?


  independent: angle of incidence

  dependent: angle of refraction

  control: material the block is made of
• Define random error?


  an error in measurement caused by factors which vary from one measurement to another.
• define systematic error?


  over the course of a number of measurements, all of those measurements are inaccurate to the same degree due to an error in set up of equipment or a repeated error in recording those results
• What is parallax Error?


  the error that occurs due to incorrect positioning of the eyes while taking a reading on a measuring scale
• Give properties of p-waves?


  they are longitudinal, they travel at the speed of sound and are twice as fast as s-waves, they travel at different speeds through solids and liquids
• Give properties of s-waves?


  they are transverse, Cannot travel through liquids
• How are p and S waves used?


  when seismic waves are produce, the difference in time between the arrival or p-waves and s-waves at different detectors can provide evidence about the location of the earthquake and the material they have traveled through
• What do s-waves shadow zone show?


  S-waves are not able to travel through the liquid outer core of the earth. this results in a large shadow zone on the opposite side of the earth to where the earthquake originate. the shadow zone provides evidence of the size of the earths core
• What do p-waves shadow zone show?


  p-wave are able to travel through the liquid outer core however they are refracted at the boundary between the semi-solid mantle and the liquid outer core, then they are refracted again at the boundary between the liquid outer core and the solid inner core. these refractions result in p-wave shadow zones. the study of these is used to determine the size of composition of the inner and outer core
• What happens during an earthquake?


  seismic waves travel outwards from the earthquake and travel in a curved path through the earth due to the earth increasing in density with depth. detectors placed around the earth measure when and where the different waves arrive
• What EM wave is used for satellite communications and why?

  microwaves- as they can pass through the atmosphere due to their large wavelength
• how Is temp linked to radiation?


  the temperature of an object determines:

  the rate at which it emits radiation

  the wavelength of the radiation it emits
• What’s a perfect black body?

  absorbs all infra red radiation incident on it