Node and Antinode

Standing Waves

Standing Waves

A standing wave is the result of two waves of the same frequency and amplitude traveling in the opposite directions through the same medium.​

Nodes are the points of no disturbance on a standing wave.

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Antinodes are where the amplitude is maximum.​

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Nodes and Antinodes

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Multiple Choice

How many nodes does this standing wave have?

• 3

• 4

• 2

• 0

​Fundamental Frequency

The fundamental frequency, or natural frequency, of a medium happens when it vibrates with the simplest standing wave: 2 nodes and 1 antinode.

Fun Fact: The fundamental frequency of the A string on a guitar is about 110 Hz!

Multiple Choice

Which image below shows a medium vibrating at its fundamental frequency?

Harmonics

The harmonic of a wave is a multiple of the fundamental frequency.

The vibrating part of the E string of a violin is 0.33 m long and has a fundamental frequency of 659 Hz.

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​In your notes packet, use these values to fill out your harmonics chart for this string.

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​Harmonic Series

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Multiple Choice

A string 1.5 meters long is vibrating in the third harmonic. The string vibrates up and down with 33 complete vibrational cycles in 10 seconds. Determine the speed of the wave.

• 1.64 m/s

• 0.45 m/s

• 0.30 m/s

• 3.30 m/s