Sound and Instruments Quiz

What is the didgeridoo primarily known for?

• Producing multiple notes

• Producing a low rumbling sound

• Being a string instrument

• Being used in ultrasound machines

Answer explanation

The didgeridoo is primarily known for producing a low rumbling sound, which is characteristic of its deep, resonant tones. It is not a string instrument, nor is it associated with ultrasound machines.

How is sound produced according to the text?

• By heating objects

• By vibrating objects

• By freezing objects

• By compressing objects

Answer explanation

Sound is produced by vibrating objects, which create pressure waves in the air. This is the fundamental principle of sound production, making 'By vibrating objects' the correct choice.

What are compressions in a sound wave?

• Regions where air particles are spread out

• Regions where air particles are bunched together

• Regions where air particles are frozen

• Regions where air particles are heated

Answer explanation

Compressions in a sound wave are regions where air particles are bunched together, creating areas of higher pressure. This contrasts with rarefactions, where particles are spread out.

What is required for a sound wave to be produced?

• A vacuum

• A solid, liquid, or gas

• Only a solid

• Only a liquid

Answer explanation

Sound waves require a medium to travel through, which can be a solid, liquid, or gas. A vacuum lacks matter, making it impossible for sound waves to propagate.

What type of wave is characterized by particles moving back and forth in the same direction as the wave is traveling?

• Transverse wave

• Longitudinal wave

• Surface wave

• Electromagnetic wave

Answer explanation

A longitudinal wave is characterized by particles moving back and forth in the same direction as the wave travels. This is in contrast to transverse waves, where particles move perpendicular to the wave direction.

Which material has the highest speed of sound according to Table 4.2.2?

• Air (at 0°C)

• Water

• Steel

• Glass

Answer explanation

According to Table 4.2.2, the speed of sound is highest in glass, surpassing that in air, water, and steel. This is due to glass's higher density and elasticity, which facilitate faster sound propagation.

What is the speed of sound in air at 18°C?

• 331 m/s

• 342 m/s

• 1440 m/s

• 4500 m/s

Answer explanation

The speed of sound in air increases with temperature. At 18°C, it is approximately 342 m/s, which is the correct answer. The other options are incorrect as they do not reflect the speed of sound at this temperature.

What is the vibrating source of sound in a piano?

• Drum skin

• Flaps of skin, called vocal cords

• String inside piano

• Speaker cone

Answer explanation

The vibrating source of sound in a piano is the string inside the piano. When a key is pressed, it causes the corresponding string to vibrate, producing sound. Other options like drum skin and vocal cords are not relevant to a piano.

What is the term for the reflected sound that is heard as an echo?

• Sonar

• Compression

• Rarefaction

• Echo

Answer explanation

The term for the reflected sound that is heard as an echo is 'Echo'. It occurs when sound waves bounce off a surface and return to the listener, creating the perception of a repeated sound.

What is the speed of sound in sea water used for sonar calculations?

• 1000 meters/second

• 1500 meters/second

• 2000 meters/second

• 2500 meters/second

Answer explanation

The speed of sound in seawater is approximately 1500 meters/second, which is commonly used in sonar calculations for underwater acoustics. This value is essential for accurate distance and depth measurements.