p2 wrong answers

• when will the flasks emit infrared radiation at the greatest rate


  during the 1st min as there is a greater temp difference between hot water and the surroundings
• describe the motion of an aeroplane as it moves towards the runway

  constant velocity/ speed
• what happens to the air surrounding the aeroplane as the height of the aeroplane above the ground increases

  the average density of the air above the aeroplane decrease
• how could a driver increase the moment about the pivot without increasing the size of the force

  apply the force further away from pivot
• explain why the temp of the brakes increases as they are used

  work done due to friction causing an increase in the internal/ thermal energy of the brakes
• the microphone is used to convert the pressure variations in sound waves into variations in

  current/ potential difference
• what is an induced magnet

  a material that becomes a magnet when it is placed in a magnetic field
• what is meant by a closed circuit

  no energy is lost
• newton's 3rd law

  every force has an opposing force
• explain how the flexible bumper reduced the risk of injury to the people in the bumper car during th ecollision

  • increased time taken for collisions to occur
  • decreases change in momentum
  • allows less risk of injury
• why has refraction not occurred (clear, straight pathway of a ray of light through a glass block)

  all points on a wave front enter the glass at the same time
• explain in terms of the wave fronts, why refraction happens at the boundary between air and glass


  • different parts of the wave front enter glass at different times
  • velocity/ speed of light is less in glass
  • one part of wave front changes speed before other parts
• explain the difference between a virtual image and a real image

  real:

  • light wave converge
  • projected onto screen

  virtual

  • light waves diverge
  • cannot be projected
• why will a fish appear to be in a different place to where it actually is

  light waves change speed and direction when they move from one medium (water) to another (air)due to their difference in their refractive indices
• how do waves act as they move to a deeper region

  • increase wave speed
  • increase wavelength
  • decrease amplitude
  • same frequency
• as you go down the electromagnetic spectrum the...

  … wavelength increases and the frequency decreases
• what is the range of wavelengths the electromagnetic waves spectrum

  10$^{-15}$ to 10$^4$
• Before taking any measurements, the student adjusted the ruler to make it vertical. Explain why adjusting the ruler was important.

  to reduce the error in measuring the extension of the spring as the ruler at an angle would make the measured extensions shorter
• Describe one technique that you could have used to improve the accuracy of the measurements taken by the student.

  use a set square to line up the bottom of the spring with the ruler scale