Week 2 - Getting familiar with waves

Q1 In a recording room an acoustic wave was measured to have a frequency of 1KHz. What would its wavelength in cm be?

Answer: The sound will be traveling through air so the velocity of sound will be 340m/s. To get the wavelength, the velocity 340m/s needs to be divided by the frequency of the wave which is 1000Hz. This gives the answer of 34cm.

Q2 If an acoustic wave is traveling along a work bench has a wavelength of 3.33m what will its frequency be? Why do you suppose that is it easier for this type if wave to be travel through solid materials?

Answer: The velocity of the sound through the bench is about  4000m/s. To get the frequency, the velocity 4000m/s needs to be divided by the wavelength of 3.33m. Its frequency then is 1.2KHz.

Q3 Research the topic “Standing Waves”. Write a detailed note explaining the term and give an example of this that occurs in real life. (Where possible draw diagrams and describe what represent)

Answer: A standing wave is a wave that resonates up and down but does not actually move. An example of this in real life would be the string on a guitar. When you pluck it, the string moves up and down but it is not travelling along the guitar.

Q4 What is meant by terms constructive and destructive interference?

Answer: Constructive interference occurs when the crest of one wave overlaps the crest of another to combine and produce a wave of increased amplitude, whereas destructive interference occurs when the crest of one wave overlaps the trough of another and no change occurs.

Q5 What aspect of an acoustic wave determines its loudness?

Answer: The higher the amplitude the louder the sound will be.

Q6 Why are decibels used in the measurement of relative loudness of acoustics waves?

Answer: Decibels are used because it is a logarithmic measurement that reflects the range of sound intensity our ears can perceive and closely correlates to the function of our ears and our perception of loudness.

Q7 Does sound travel under water? If so what effect does the water have?

Answer: Sound does travel under water. Sound in water travels faster than in air because water particles are closer together than in air so the vibrations will happen quicker thus the sound will travel faster.