Harmonics

The figure represents a string of length L, fixed at both ends, vibrating in several harmonics. Which string shows the 4th harmonic?

• A

• B

• C

• D

• E

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NGSS.HS-PS4-1

What number harmonic is shown in A

• 1

• 2

• 3

• 4

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NGSS.HS-PS4-1

Even numbered harmonics do not form in a closed pipe because

• the pipe “fits” only an odd number of quarter wavelengths

• the pipe “fits” only an even number of quarter wavelengths

• the pipe cannot put an anti-node at the open end

• the pipe cannot get enough air to vibrate in the pipe at these lengths

Tags

NGSS.HS-PS4-1

A stretched string is observed to have four equal segments in a standing wave driven at a frequency of 480 Hz.  What driving frequency will set up a standing wave with five equal segments?

• 600 Hz

• 360 Hz

• 240 Hz

Tags

NGSS.HS-PS4-1

A 0.588-m string is tightly clamped at both ends. If the lowest standing wave frequency of the string is  326 Hz, how fast do waves travel on this string?

• 383 m/s

• 475 m/s

• 582 m/s

• 724 m/s

Tags

NGSS.HS-PS4-1

A string that is 2.0 meters long is fixed at both ends and tightened until the wave speed is 18 m/s. What is the frequency of the standing wave shown in the figure?

• 27 Hz

• 54 Hz

• 81 Hz

• 110 Hz

Tags

NGSS.HS-PS4-1

The moving black dot is called:

• a node

• an anti-node

• an anti-amplitude

• the wangy bit

Tags

NGSS.HS-PS4-1

How many antinodes does this standing wave have?

• 5

• 6

• 7

• 8

Tags

NGSS.HS-PS4-1

A horn has a fundamental frequency of 81 Hz. What is its 5th harmonic in Hz? (Just write the number, don't include the unit.)

Answer explanation

The 5th harmonic has a frequency 5 times the fundamental.

Tags

NGSS.HS-PS4-1

A saxophone is...

• an open tube, and only has odd harmonics.

• an open tube, and has all harmonics.

• a closed tube, and only has odd harmonics.

• a closed tube, and has all harmonics.

Answer explanation

A closed tube has one end that is closed (the reed) and one end that is open (the bell). A closed tube has only odd harmonics. The 1st (fundamental), 3rd, and 5th harmonics are shown.

Tags

NGSS.HS-PS4-1