Conceptual Physics (TESC) Chapter 20

A piano tuner knows that a key on the piano is tuned to the frequency of his tuning fork when he strikes them at the same time and the number of beats he hears each second is

0.

A 340-hertz sound wave travels at 340 m/s in air with a wavelength of

1 m.

A wave having a frequency of 1000 hertz vibrates at

1000 cycles per second.

Suppose you sound a 1056-hertz tuning fork at the same time you strike a note on the piano and hear 2 beats/second. You tighten the piano string very slightly and now hear 3 beats/second. What is the frequency of the piano string?

1059 hertz

The approximate range of human hearing is

20 hertz to 20,000 hertz.

A general rule for estimating the distance in kilometers between an observer and a lightning bolt is to count the number of seconds between seeing the lightning and hearing it, and dividing by

3.

Two tuning forks produce sounds of wavelengths 3.4 meters and 3.3 meters. Approximately what beat frequency is produced?

3.0 hertz

The beat frequency produced when a 240 hertz tuning fork and a 246 hertz tuning fork are sounded together is

6 hertz.

Which type of radio wave produces the least static in a radio receiver?

FM

Xenon has atomic number 54, while Krypton has atomic number 36. Given that both gases are at the same temperature, in which medium does sound travel faster?

Krypton gas

Longitudinal waves of different lengths are traveling though a long metal rod. Those that travel at the greatest speed are

None of the above choices are correct

We are best at hearing

None of the above choices are true.

Sound waves can interfere with one another so that no sound results.

True

Sound waves cannot travel in

a vacuum.

For AM radio, the A stands for

amplitude.

The least energy required to produce forced vibration in an object occurs

at its natural frequency.

When the handle of a tuning fork is held solidly against a table, the sound becomes louder and the time that the fork keeps vibrating

becomes shorter.

Refraction of sound can occur in

both air and water.

A dolphin perceives its environment by the sense of

both sight and sound.

In the case of radio, which has the higher frequency?

carrier wave

Repeatedly tap the side of a drinking glass with a spoon while filling it with water and you will notice that the pitch of the sound

decreases.

In perceiving its environment, a dolphin makes use of

echoes; the Doppler effect; and ultrasound.

Inhaling helium increases the pitch of your voice. One reason for this is that sound travels

faster in helium than in air.

For FM radio, the F stands for

frequency.

A neon atom has a larger atomic number than a helium atom. At the same temperature and pressure, how does the speed of sound in helium gas compare to the speed of sound in neon gas?

greater in helium than in neon

In which one of these media does sound travel the fastest?

ice

The energy of sound in air eventually becomes

increased internal energy of the air.

The phenomenon of beats results from sound

interference.

Resonance can be looked at as forced vibration with the

least amount of energy input.

The wavelengths of sound that carry farther in air are relatively

long.

A sound wave is a

longitudinal wave.

Compressions and rarefactions are characteristic of

longitudinal waves.

The frequencies of sound that carry farther in air are

low.

An explosion occurs 34 km away. Since sound travels at 340 m/s, the time it takes for the sound to reach you is

more than 20 seconds.

Double the frequency of sound and you also double its

none of these

A 1056-hertz tuning fork is sounded at the same time a piano note is struck. You hear three beats per second. What is the frequency of the piano string?

not enough information to be certain

A sound source of high frequency emits a high

pitch.

Which doesn't belong to the same family?

radio waves

Reverberation is actually a case of

re-echoed sound.

Caruso is said to have made a crystal chandelier shatter with his voice. This is a demonstration of

resonance.

When you tune a radio to a certain station, you match the frequency of the internal electrical circuit to the frequency of the wanted radio station. In so doing you are employing the principle of

resonance.

The natural frequency of an object depends on its

size, shape and elasticity.

The object with the highest natural frequency is a

small bell.

A base fiddle is louder than a harp because of its

sounding board.

The explanation for refraction must involve a change in

speed.

Sound travels faster in

steel.

On some days, air nearest the ground is colder than air that is higher up. On one of these days, sound waves

tend to be refracted downward.

The speed of a sound wave in air depends on

the air temperature.

Compressions and rarefactions normally travel in

the same direction in a wave.

When the speed of sound near the ground is greater than it is at higher altitudes, the sound tends to be bent

upward

Sound refraction depends on the fact that the speed of sound is

variable.

The source of every sound is something that is

vibrating.

Sound travels faster in air if the air temperature is

warm.

In designing a music hall, an acoustical engineer deals mainly with

wave interference.

Double the frequency of a sound and you halve its

wavelength.

Sound will be louder if a struck tuning fork is held

with its base against a table top.