WAVES (PART 1)

Question 1

1. What is the information about the environment carried by?

Answer 1

• light waves
• sound waves

Question 2

2. How is sound wave interpretation used in Medicine?

Answer 2

• physicians use stethoscopes to listen to sounds in the
  body
• they tap on parts of the body as a diagnostic tools
• ultrasonography

Question 3

3. What is Ultrasonography?

Answer 3

• it is a non destructive form of imaging
• it makes use of sound at frequencies above our
  hearing range
• it uses this to provide us with images

Question 4

4. What is our Hearing Range?

Answer 4

• 20 Hz to 20 kHz

Question 5

5. What happens when the waves are sent to an object?

Answer 5

• they are reflected

Question 6

6. What exists between the transmission of the probe beam and the arrival of the reflected acoustic pulses at the detector?

Answer 6

• a delay time

Question 7

7. What gives us the relative location of the object?

Answer 7

• the delay time between the transmission of the probe
  beam and the arrival of the reflected acoustic pulses
  at the detector

Question 8

8. What is the basis for measuring blood flow direction, turbulence and speed?

Answer 8

• the shifting of the acoustic frequency
• when the ultrasound reflects from a moving target
• this is known as the Doppler effect

Question 9

9. What happens when a wave propagates?

Answer 9

• each spatial point on the wave is oscillating
• it oscillates in Simple Harmonic Motion

Question 10

10. What kind of motion is Oscillatory motion?

Answer 10

• periodic
• repeated movements

Question 11

11. What is the wave a result of?

Answer 11

• oscillations
• each oscillator is in a strict phase relationship with
  the other point

Question 12

12. What does each Oscillator have?

Answer 12

• the same spring constant
• the same mass
• oscillates with the same amplitude
• it has the same period
• it has the same frequency

Question 13

13. Within each Oscillator, what occurs with the oscillations?

Answer 13

• each oscillation is slightly ahead or behind its neighbours

Question 14

14. What is a Propagating Wave?

Answer 14

• it is a self-sustaining disturbance of a medium
• it travels from one point to another
• it carries energy
• it carries momentum

Question 15

15. What are Mechanical Waves?

Answer 15

• they are summative phenomena
• they arise from the motion of particles

SUMMATIVE = increasing or increased in quantity

Question 16

16. What happens to the particles when a wave advances?

Answer 16

• the particles of the medium will only oscillate in place

Question 17

17. How is Simple Harmonic Motion related to the wave motion?

Answer 17

• wave motion involves particles that oscillate up and down in place

Question 18

18. How does a wave that has been generated by a hand and a string occur?

Answer 18

• a wave will be generated on the string
• it starts from the sinusoidal vibration of the hand

SINUSOIDAL= having the form of a sine curve

Question 19

19. Where is energy carried from in this situation:

Answer 19

• the energy is carried by the wave
• it is carried from the source to the right
• it is carried along the string

Question 20

20. What is the direction of energy transport also called?

Answer 20

• it is called the direction of propagation of the wave
• it can also be called the line of propagation of the wave

Question 21

21. What happens with each particle of the string in this diagram?

Answer 21

• each particle of the string vibrates up and down
• this vibration is perpendicular to the line of
  propagation
• this can be seen with the particles at Point C

Question 22

22. What is a Transverse Wave?

Answer 22

• it is a wave that travels through the medium
• the medium is oscillating in a direction that is
  perpendicular to the direction in which the wave is
  propagating
• this means that the motion of the medium of the wave
  is transverse

Question 23

23. What kinds of waves are typical Transverse waves?

Answer 23

• they are electromagnetic waves

Question 24

24. What are Longitudinal Waves?

Answer 24

• they are waves which travel through a medium
• each spatial point in the medium is oscillating
• it oscillates in the same direction as the wave is
  propagating in

Question 25

25. What kinds of waves are Typical Longitudinal Waves?

Answer 25

• they are sound waves

Question 26

26. What are the top points of a wave called?

Answer 26

• Crests

Question 27

27. What are the bottom points of the wave called?

Answer 27

• troughs

Question 28

28. What happens to the troughs and the crests of the wave as it goes on?

Answer 28

• the crests and the troughs will move to the right
• they will move with a speed of v
• this is known as the wave speed

Question 29

29. What is the Amplitude of a wave?

Answer 29

• it is the maximum disturbance that is undergone during a vibrational cycle

Question 30

30. What is the Wavelength (λ) of a wave?

Answer 30

• it is the distance between two consecutive points of
  the waves
• this can be the distance between two troughs or
  between two crests
• it is a length
• it is measured in metres
• it is the distance along the direction of propagation
  between corresponding points of the wave

Question 31

3. What is the Period (T) of a wave?

Answer 31

• it is the time it takes the wave to go through one
  complete cycle
• it is the number of seconds per cycle

Question 32

32. What is the Frequency (f) of a wave?

Answer 32

• it is the number of cycles per second

Question 33

33. How is the Frequency (f) of a wave calculated?

Answer 33

Question 34

34. What happens to the wave within time (T)?

Answer 34

• the crest will move
• it will move with a speed (v)
• it will move a distance (W) to the right

Question 35

35. How do we calculate the speed of a wave?

Answer 35

• this relation holds for all waves
• ▵x = displacement
• λ= wave length
• T= period
• t= time

NB: this relation holds for all waves