Module 4 - Waves (Stationary waves)

Question 1

What are the conditions for a standing wave to be formed

Answer 1

• Two progressive waves of the same frequency
• Travelling in opposite directions superpose.
• Coherent
• Same wavelength

Question 2

How are standing waves characterised

Answer 2

• With nodes and antinodes

Question 3

What is meant by a progressive wave

Answer 3

A wave that transfers energy from one location to another by oscillations of the medium through which the wave travels, and no net transfer of mass

Question 4

What is meant by a standing wave

Answer 4

A wave that has no net energy transfer

Question 5

Why is there no net energy transfer in standing waves

Answer 5

• The wave oscillates between 2 nodes and so energy is transferred strictly between these nodes and not between locations

Question 6

What are nodes and how are they formed

Answer 6

• Regions in the standing wave that has 0 displacement all the time, this is because at that point the 2 transmitted waves superpose in antiphase

Question 7

What is the name of the waves that make the standing wave

Answer 7

• Transmitted waves

Question 8

What are antinode and how are they formed

Answer 8

• Regions in the standing waves where there is maximum displacement, this is because at that point the 2 waves superpose in phase

Question 9

Where are antinodes found

Answer 9

In the centre of 2 adjacent nodes

Question 10

What is the distance between 2 adjacent nodes

Answer 10

λ/2, where λ is the wavelength of the original wave

Question 11

Describe the difference between progressive waves and standing waves in terms of energy transfer

Answer 11

P: Energy is transferred in teh direction of the wave
S: No net energy transfer

Question 12

Describe the difference between progressive waves and standing waves in terms of wavelength

Answer 12

P: The wavelength is equal to the minimum distance between 2 adjacent points oscillating in phase
S: The wavelength is equal to twice the distace between adjacent nodes

Question 13

Describe the difference between progressive waves and standing waves in terms of phase

Answer 13

P: Phase changes accross one oscillation
S: All point on the wave between 2 adjacent points are inphase, all points on opposite sides of the node are in antiphase

Question 14

Describe the difference between progressive waves and standing waves in terms of Amplitude

Answer 14

P: All parts of the wave have the same amplitude, assuming no energy is lost to the surroundings
S: Maximum amplitude occurs at the antinode

Question 15

What is meant by the fundamental frequency of a string

Answer 15

• The lowest frequency at which a standing wave can be formed using a specific string

Question 16

For a standing wave with 2 nodes at both ends, what is the relationship between the harmonic and the frequency of the wave as a multiple of f0

Answer 16

• As the harmonic number increases the frequency increases proportionally

Question 17

What are the 3 scenarios where stationary waves can be created in harmonics

Answer 17

• Vibrating strings with nodes at both ends
• Tubes open at both ends with antinodes at both ends
• Tubes closed at one end with a nod at one end and an antinode at another

Question 18

What is a harmonic

Answer 18

An integer multiple of the fundamental frequency