JEE Main & Advanced Physics Wave Mechanics Terms Related to the Application of Stationary Wave

(1) Note : Any musical sound produced by the simple harmonic oscillations of the source is called note.

(2) Tone : Every musical sound consists of a number of components of different frequencies every component is known as a Tone.

(3) Fundamental note and fundamental frequency : The note of lowest frequency produced by an instrument is called fundamental note. The frequency of this note is called fundamental frequency.

(4) Harmonics : The frequency which are the integral multiple of the fundamental frequency are known as harmonics e.g. if n be the fundamental frequency, then the frequencies n, 2n, 3n .... are termed as first, second, third .... harmonics.

(5) Overtone : The harmonics other than the first (fundamental note) which are actually produced by the instrument are called overtones. e.g. the tone with frequency immediately higher than the fundamental is defined as first overtone.

(6) Octave : The tone whose frequency is doubled the fundamental frequency is defined as Octave.

(i) If  \[{{n}_{2}}=2{{n}_{1}}\] it means \[{{n}_{2}}\] is an octave higher than \[{{n}_{1}}\] or \[{{n}_{1}}\] is an octave lower than \[{{n}_{2}}\].

(ii) If \[{{n}_{2}}={{2}^{3}}{{n}_{1}},\] it means \[{{n}_{2}}\] is 3-octave higher or \[{{n}_{1}}\] is 3-octave lower.

(iii) Similarly if \[{{n}_{2}}={{2}^{n}}{{n}_{1}}\] it means \[{{n}_{2}}\] is n-octave higher \[{{n}_{1}}\] is n ­octave lower.

(7) Unison : If the interval is one i.e. two frequencies are equal then vibrating bodies are said to be in unison.

(8) Resonance : The phenomenon of making a body vibrate with its natural frequency under the influence of another vibrating body with the same frequency is called resonance.