2024

• equation linking frequency, wavelength and wave speed

  $v=$$f\times\lambda$
• elastic potential energy unit

  Joules/J
• How can the compression of the spring be determined

  -calculate the weight of the mass of the spring

  -use equation e=f

  k
• Why should the experiment be done on the laboratory floor rather than a table

  masses could fall off the spring so less likely to cause injury if done on the floor
• spring constant unit

  N/m
• Electromagnetic waves

  -grouped according to their wavelength and frequency

  -are transverse waves

  -can travel through a vacuum

  -They transfer energy

  -speed in air/vacuum
• What is meant by a transverse wave

  Vibrations are perpendicular to the direction of energy transfer.
• Which group of electromagnetic waves is used for satellite communication

  microwaves
• The human eye can ONLY detect

  visible light (is the only group of Electromagnetic waves)
• Which colour of visible light has the shortest wavelength

  Violet (purple)
• Describe a risk linked to each group of high-frequency electromagnetic waves

  -ULTRAVIOLET can cause skin to age or skin cancer

  -X-rays/GAMMA RAYS increase the risk of cancers

  -all can cause mutations in DNA /genes
• magnetic flux density unit

  Tesla (t)
• The permanent magnet exerts an equal and opposite force on the electromagnet

  e.g of Newton's 3rd law
• Give 3 changes to the electromagnet that would increase the force exerted on the permanent magnet

  1-Add more turns to the coil/electromagnet

  2-increase the current in the coil/electromagnet

  3- Move the electromagnet closer to the permanent magnet
• Give 2 changes to the electromagnet that would reverse the direction of the force exerted on the permanent magnet

  1-reverse the current in the coil

  2-turn the electromagnet around(to reverse the poles)

  3-wrap the coil(around the iron core)in the opposite direction
• How can the reaction time of the driver be used to calculate the thinking distnace

  Multiply the speed of the car by the reaction time.
• What happens to the weight of a rocket as it accelerates upwards

  gravitational field strength decreases; therefore, the weight decreases.
• Describe a method the teacher could use to investigate how the frequency of the wave affects the wavelength.

  [4 marks]

  • Use the signal generator to adjust the frequency.
  • Keep the number of masses the same.
  • Move the wooden bridge.
  • Observe a steady/stationary wave pattern.
  • Use the metre rule to measure the wavelength.
  • Repeat using different values of frequency.
  • Repeat for different stationary wave patterns.
• 02.1When a spring is compressed, the elastic potential energy of the spring increases.Explain why compressing the springs in the floor helps the gymnast to jump higher.Use ideas about energy in your answer.

  [2 marks]

  As a spring decompresses, the spring exerts a force on the gymnast, so work is done on the gymnast.
• The electromagnetic waves are produced by oscillations in the transmitter of the mobile phone.Explain how oscillations in the transmitter enable information to be transferred to the detector in the laptop.

  [4 marks]

  Radio waves are produced by the transmitter.

  The detector absorbs the wave’s energy, which produces an alternating current with the same frequency as the transmitted waves.
• At a height of 40 km, the rocket stopped burning fuel.The rocket continued upwards to its maximum height of 60 km.Explain why the velocity of the rocket decreased between a height of 40 km and a height of 60 km.

  [3 marks]

  Gravitational force acts on the rocket (in the opposite direction to the motion of the rocket) and there are no forces in the direction that the rocket is moving, so resultant force is towards the Earth.
• Using parachutes causes the passenger module to fall with a lower terminal velocity than if parachutes were not used.Explain why the parachutes allow the passenger module to fall with a lower terminal velocity.

  [3 marks]

  Parachutes increase the effective area, so there is the same air resistance at a lower speed.

  So resultant force is zero at a lower speed (with the parachutes open).