Vibrations and Sound

Question 1

Overtones

Answer 1

Frequencies which are multiples of a certain frequency are called overtones of that frequency.
If f is a given frequency, 2f is the first overtone and 3f is its second overtone

Question 2

Loudness

Answer 2

The loudness of a sound wave depends on the amplitude of the sound wave. The greater the amplitude the greater the loudness

Question 3

Pitch

Answer 3

The pitch of a note depends on the frequency of the sound wave. The higher the frequency the higher the pitch, the lower the frequency the lower the pitch

Question 4

Quality

Answer 4

The quality of a musical note depends on the number of overtones present in the note and the relative strengths of the different overtones present

Question 5

Frequency Limits of Audibility

Answer 5

The frequency limits of audibility are the highest and lowest frequencies that can be heard by a normal human ear. The range is 20 Hz to 20,000 Hz

Question 6

Resonance

Answer 6

If the frequency of a periodic force applied to a body is the same as or very near to its natural frequency that body will vibrate with very large amplitude. This phenomenon is called resonance.
Or
Resonance is the transfer of energy between two bodies of the same natural frequency.

Question 7

Sound Intensity at a Point

Answer 7

The sound intensity (I) at a point is the rate at which sound energy is passing through unit area at right angles to the direction in which the sound is travelling at that point, i.e. the amount of sound energy passing through 1 m*2 per second
Sound Intensity = Power/Area

Question 8

Unit of Sound Intensity

Answer 8

The unit of sound intensity is the watt per square metre

W / m*2

Question 9

Threshold of Hearing

Answer 9

The threshold of hearing is the smallest sound intensity detectable by the average human ear at a frequency of 1 kHz. Its value is 1 x 10-12 W/m2

Question 10

Sound Intensity Level

Answer 10

Sound intensity level is measured in decibels (dB)

Question 11

Fundamental Frequency of a String

Answer 11

A string vibrating with an anti-node at its centre and a node at each end is vibrating at its fundamental frequency

Question 12

Harmonics

Answer 12

Frequencies which are multiples of a certain frequency f are called harmonics. f is called the fundamental frequency or the first harmonic. If f is the first harmonic, 2f is the second harmonic and 3f is the third harmonic