Sound Quiz 1

Vibrations in the air caused by pressure fluctuations are

• mechanical waves

• longitudinal waves

• sound waves

• all of the above

The 3 types of sounds are

• 1. infrasonic, 2. sonic and 3. ultrasonic

• vibrations made by vibrating 1. membranes, 2, air columns or 3. strings or bars.

• 1. radio waves, 2. microwaves and 3. Mexican waves

• none of the above

Answer explanation

Infrasonic: It is a sound with a frequency of less than 20Hz. Elephants use Infrasonic sounds to interact with herds hundreds of km away.

Sonic: It is a sound with the frequency between 20 to 20,000Hz. ...

Ultrasonic: It is a sound with a frequency more than 20,000Hz.

List as many characteristics of sound as you can.

Answer explanation

Did you mention any of the below answers?

1. amplitude

2. wavelength and waveform

3. time period

4. speed (or velocity)

5. pitch (based on frequency)

6. loudness (based on amplitude)

7. timbre (based on sound source/ quality of sound)

8. reflection or echo

9. refraction (sound travels more distance at nighttime than daytime)

10. diffraction (bending of sound waves around corners)

Unwanted sound is called....

Speed of sound increases with

• density of medium

• temperature of medium

• humidity of air

• all of the above

Instruments that produce sound are called sources of sound.

• True

• False

Only artificial sounds are produced by vibrations of strings/rods,

membranes, bars or air columns.

• True

• False

Number of vibrations of a sound source, produced in a second is called the

wavelength.

• True

• False

Which statement is false?

• The limits of hearing of human is 20 Hz - 20 000 Hz.

• Inaudible sounds are in the sonic range.

• There are three categories of musical instruments, according to the part that

  vibrates when producing sound.

• Sound can be used to improve the quality of life.

How do you increase the pitch in string instruments?

• shorten the length of string and tighten the string

• shorten the length of string and loosen the string

• lengthen the string and tighten the string

• lengthen the string and loosen the string

Answer explanation

Also the thickness of string affects the pitch. Thinner string gives higher pitch.