12.5

Question 1

What is a fundamental mode of vibration

Answer 1

A vibration at the fundamental frequency

Question 2

What is the fundamental frequency

Answer 2

Lowest frequency at which an object can vibrate

Question 3

What are harmonics

Answer 3

Whole number multiple of fundamental frequency

Question 4

What type of waves are produced on strings

Answer 4

Stationary waves

Question 5

What is the relationship of a string’s length L at the first harmonic

Answer 5

• λ = 2L (/1)

• f0 = V / 2L
• v=fλ

Question 6

What is the relationship of a string’s length L at the second harmonic

Answer 6

• λ = L (2L/2)

• f1 = V / L
• v=fλ

Question 7

What is the relationship of a string’s length L at the third harmonic

Answer 7

• λ = 2L / 3

• f2 = 3V / 2L
• v=fλ

Question 8

Why are the ends of a string always nodes (harmonics)

Answer 8

The points are fixed

Question 9

What is the relationship between wave speed, mass, and tension

Answer 9

v = (root) T / (m / L)

Question 10

Describe Melde’s experiment (investigating stationary waves on strings)

Answer 10

• Vibration generator is used to change the frequency of wave on stretched string until specific harmonic produced
• Actual node is just shy of the vibration generator (generator itself vibrates so is not a node)
• No stationary wave will be formed if the vibration generator is not set to integer multiple of f0
• Length of string can be changed
• fixed end can be replaced with pulley
• different masses attached to string to change tension