### 1. Which of the following wavelengths of a sound wave would a human be able to hear?

a. 1400 m

b. 140 m

c. 14 m

d. 0.014 m

Answer: From the passage we know that the human ear is sensitive to frequencies between 20 Hz and 20,000 Hz. For this problem one should know that the speed of sound is 342 m/s and use the equation v = f.

When using = v/f and using our range of 20 Hz and 20,000 Hz this would allow us to calculate the following:

= 342 m/s / 20 Hz = 17.1 m

= 342 m/s / 20,000 Hz = 0.0171 m

Therefore, our answer choice must be between 17.1 m and 0.0171 m leaving answer choice C as the correct answer.

### 2. The human ear is sensitive to:

a. Intensity and Frequency

b. Frequency and Wavelength

c. Intensity, Wavelength and Frequency

d. Intensity and Wavelength

Answer: Frequency of different soundwaves is what causes the human eardrum to vibrate, and it is the change in these sound frequencies that allows us to distinguish one sound from another. Additionally, the human ear is sensitive to sound intensity which is the degree of loudness of the incoming sound. This makes answer choice A the correct answer. The speed of sound can change based on the air temperature and density and if the frequency is constant, this would cause a change in the wavelength. Essentially meaning if the human ear were sensitive to wavelength changes, a person’s voice would sound different each time there was a change in temperature which is why the other answer choices are incorrect as they have wavelength as part of the answer.

### 3. When listening to a recording of one’s voice many often comment that their recorded voice does not sound like the voice they hear when they speak out loud. What is a potential reason for this?

a. You can hear your spoken voice with a higher frequency compared to your taped voice. This is because bone transmits higher frequencies better than air does.

b. You can hear your spoken voice with a lower frequency compared to your taped voice. This is because bone transmits higher frequencies better than air does.

c. You can hear your spoken voice with a higher frequency compared to your taped voice. This is because bone transmits lower frequencies than air does.

d. You can hear your spoken voice with a lower frequency compared to your taped voice. This is because bone transmits lower frequencies than air does.

Answer: Part of our speech is transmitted through bone directly to our ear and does not travel through the air. It is important to note that bone transmits sounds at lower frequencies as compared to air and bone has a tendency to suppress frequencies that are higher. Therefore, when we hear our own voice when speaking out loud, we hear a deeper tone to our voices as compared to other listeners, making choice D correct.