Waves Active Recall ANSWERS:
3.3.1 Progressive and stationary waves:
1. Define progressive wave 1. A progressive wave is one that transfers
energy without transferring any physical
matter/the medium itself.
2. Define displacement of a 2. The displacement of a wave is the distance
wave of a point of a wave moved from its starting
position.
3. Define amplitude of a wave 3. The maximum displacement point of a wave
from the equilibrium position.
4. Define wavelength of a wave 4. The distance between 2 points on successive
waves for waves in phase with each other.
5. Define period of a wave 5. The time it takes for a wave to undergo one
full cycle or one full oscillation.
6. Define frequency of a wave 6. The number of waves passing a point in one
second.
7. Define speed of a wave 7. The distance travelled by a point of a wave
over a specified unit time.
8. What equation links speed, 8. V=fλ
frequency and wavelength?
9. What equation links 9. F=1/T
frequency and time period?
10. What is phase difference? 10.Phase difference is the difference in position
of the waves in terms of pi.
11. When the crests or troughs of 11.In phase
a wave are aligned what is the phase
difference?
12. When the crests and troughs 12.Out of phase/antiphase
of a wave are aligned what is the
phase difference?
13. How is phase difference 13.Fractions of a wavelength, radians, degrees
measured?
14. How do particles oscillate in 14.They oscillate about fixed points
mechanical waves?
15. What are the two types of 15.Transverse and longitudinal
waves?
16. Define transverse wave 16.The wave oscillates perpendicular to the
direction of energy transfer and wave travel.
17. Name four examples of 17.Guitar string vibrations, radio waves, x rays,
transverse waves gamma rays, micro waves, light
18. Define longitudinal wave 18.The wave oscillates parallel to the direction
of energy transfer and wave travel.
19. What is a compression? 19.A compression is a region of increased
pressure
20. What is a rarefaction? 20.A rarefaction is a region of decreased
pressure
21. Name four examples of 21.A slinky being pushed horizontally, sound
longitudinal waves waves, ultrasound waves, seismic P waves
22. How is energy transmitted 22.The particles in the medium vibrate as they
through a longitudinal wave? are given energy, the compressions cause
the particles near to vibrate with more
energy, which produces a compression later
in the medium.
23. Define polarisation 23.Particle oscillations only occur in one
, direction perpendicular to the wave’s energy
transfer and direction of wave travel.
24. What kind of waves can be 24.Transverse as they oscillate in any plane
polarised? Why? perpendicular to the propagation direction.
25. Why can’t longitudinal waves 25.They oscillate parallel to the direction of
be polarised? travel.
26. How can waves be polarised? 26.Through a polariser or polarising filter. This
makes it so only oscillations in a certain
plane can be transmitted.
27. Explain how Polaroid glasses 27.The Polaroid glasses have particular lenses
reduce glare on the surface of water with transmission axes which are oriented
vertically, which means horizontally polarised
light cannot pass through. This is beneficial
to wearers as the reflection of light will
undergo partial polarisation, so the lenses
will reduce the glare on the surface of water
or any other reflective surface and you can
see under the surface better.
28. Explain how Polaroid filters 28.Polaroid filters work by a polarising lens
work which has a transmission axes, so the light
reflected by the surface of the water is
partially polarised in the horizontal plane so
cannot be seen through the polarising lens.
Light from an underwater object is refracted
by the water and therefore cannot be plane
polarised, but as the glare is reduced, the
light from the underwater object can be
more intense than the glare, therefore
showing up brighter in the photo.
29. Explain how the polarisation 29.Radio and microwaves are polarised either
of radio and microwave signals work horizontally or vertically, so the receiving
aerial needs to be mounted either vertical or
horizontal to point towards the transmitter.
30. What is a stationary wave? 30.A stationary wave is produced by the
superposition of two waves travelling
towards each other in opposite directions.
These waves need to be the same frequency
and amplitude.
31. How is a stationary wave 31.When two waves of the same frequency and
formed? amplitude travelling in opposite directions
towards each other superpose. Typically
formed with the reflection of a travelling
wave.
32. What do stationary waves do 32.They store energy, unlike progressive waves
with energy? which transfer energy.
33. What is a node? 33.A node is a region of no vibration
34. What is an antinode? 34.An antinode is a region of maximum
amplitude vibration.
35. Are nodes fixed or can they 35.Nodes are fixed and they don’t move along
move in the horizontal direction? the string. Only antinodes move in the
vertical direction.
36. What is the phase difference 36.Zero between two consecutive nodes
of points between nodes?
37. What is the phase difference 37.Out of phase
3.3.1 Progressive and stationary waves:
1. Define progressive wave 1. A progressive wave is one that transfers
energy without transferring any physical
matter/the medium itself.
2. Define displacement of a 2. The displacement of a wave is the distance
wave of a point of a wave moved from its starting
position.
3. Define amplitude of a wave 3. The maximum displacement point of a wave
from the equilibrium position.
4. Define wavelength of a wave 4. The distance between 2 points on successive
waves for waves in phase with each other.
5. Define period of a wave 5. The time it takes for a wave to undergo one
full cycle or one full oscillation.
6. Define frequency of a wave 6. The number of waves passing a point in one
second.
7. Define speed of a wave 7. The distance travelled by a point of a wave
over a specified unit time.
8. What equation links speed, 8. V=fλ
frequency and wavelength?
9. What equation links 9. F=1/T
frequency and time period?
10. What is phase difference? 10.Phase difference is the difference in position
of the waves in terms of pi.
11. When the crests or troughs of 11.In phase
a wave are aligned what is the phase
difference?
12. When the crests and troughs 12.Out of phase/antiphase
of a wave are aligned what is the
phase difference?
13. How is phase difference 13.Fractions of a wavelength, radians, degrees
measured?
14. How do particles oscillate in 14.They oscillate about fixed points
mechanical waves?
15. What are the two types of 15.Transverse and longitudinal
waves?
16. Define transverse wave 16.The wave oscillates perpendicular to the
direction of energy transfer and wave travel.
17. Name four examples of 17.Guitar string vibrations, radio waves, x rays,
transverse waves gamma rays, micro waves, light
18. Define longitudinal wave 18.The wave oscillates parallel to the direction
of energy transfer and wave travel.
19. What is a compression? 19.A compression is a region of increased
pressure
20. What is a rarefaction? 20.A rarefaction is a region of decreased
pressure
21. Name four examples of 21.A slinky being pushed horizontally, sound
longitudinal waves waves, ultrasound waves, seismic P waves
22. How is energy transmitted 22.The particles in the medium vibrate as they
through a longitudinal wave? are given energy, the compressions cause
the particles near to vibrate with more
energy, which produces a compression later
in the medium.
23. Define polarisation 23.Particle oscillations only occur in one
, direction perpendicular to the wave’s energy
transfer and direction of wave travel.
24. What kind of waves can be 24.Transverse as they oscillate in any plane
polarised? Why? perpendicular to the propagation direction.
25. Why can’t longitudinal waves 25.They oscillate parallel to the direction of
be polarised? travel.
26. How can waves be polarised? 26.Through a polariser or polarising filter. This
makes it so only oscillations in a certain
plane can be transmitted.
27. Explain how Polaroid glasses 27.The Polaroid glasses have particular lenses
reduce glare on the surface of water with transmission axes which are oriented
vertically, which means horizontally polarised
light cannot pass through. This is beneficial
to wearers as the reflection of light will
undergo partial polarisation, so the lenses
will reduce the glare on the surface of water
or any other reflective surface and you can
see under the surface better.
28. Explain how Polaroid filters 28.Polaroid filters work by a polarising lens
work which has a transmission axes, so the light
reflected by the surface of the water is
partially polarised in the horizontal plane so
cannot be seen through the polarising lens.
Light from an underwater object is refracted
by the water and therefore cannot be plane
polarised, but as the glare is reduced, the
light from the underwater object can be
more intense than the glare, therefore
showing up brighter in the photo.
29. Explain how the polarisation 29.Radio and microwaves are polarised either
of radio and microwave signals work horizontally or vertically, so the receiving
aerial needs to be mounted either vertical or
horizontal to point towards the transmitter.
30. What is a stationary wave? 30.A stationary wave is produced by the
superposition of two waves travelling
towards each other in opposite directions.
These waves need to be the same frequency
and amplitude.
31. How is a stationary wave 31.When two waves of the same frequency and
formed? amplitude travelling in opposite directions
towards each other superpose. Typically
formed with the reflection of a travelling
wave.
32. What do stationary waves do 32.They store energy, unlike progressive waves
with energy? which transfer energy.
33. What is a node? 33.A node is a region of no vibration
34. What is an antinode? 34.An antinode is a region of maximum
amplitude vibration.
35. Are nodes fixed or can they 35.Nodes are fixed and they don’t move along
move in the horizontal direction? the string. Only antinodes move in the
vertical direction.
36. What is the phase difference 36.Zero between two consecutive nodes
of points between nodes?
37. What is the phase difference 37.Out of phase
