Fundamental frequency

Definition

The fundamental frequency is the lowest frequency at which a system oscillates. It is also known as the first harmonic and determines the pitch of a sound in musical instruments.

5 Must Know Facts For Your Next Test

1. The fundamental frequency is inversely proportional to the length of the vibrating object.
2. In a vibrating string, the fundamental frequency occurs when there are two nodes at each end and one antinode in the middle.
3. For a given string, increasing tension will increase its fundamental frequency.
4. In wind instruments, the fundamental frequency is determined by the length and shape of the air column.
5. The fundamental frequency can be calculated using $f_1 = \frac{v}{2L}$ for strings and open tubes, where $v$ is the wave speed and $L$ is the length.

Review Questions

• What happens to the fundamental frequency if you increase the tension on a string?
• How does the length of an air column in a wind instrument affect its fundamental frequency?
• Calculate the fundamental frequency of a string that is 1 meter long with a wave speed of 340 m/s.

Related terms

Harmonics:

Frequencies that are integer multiples of the fundamental frequency.

Resonance:

A phenomenon where an object vibrates at maximum amplitude at specific frequencies.

Node:

A point along a standing wave where there is no motion (displacement).