Click and drag the red line to change the frequency of the vibrator
Consider a stretched string that is fixed to a wall at one end and is attached
at the other end to a vibrator which sends a continuous sinusoidal wave along
the string. If you change the frequency of the vibrator, you will notice that at
certain frequencies, standing waves with very large displacements are set up on
the string.
The phenomenon of producing oscillation amplitudes on the string
which are much larger that the vibrator amplitude is called resonance. The
standing waves at which resonance may occur are called oscillation modes
or normal modes of the string and the frequencies at which these oscillation modes
are generated are called resonant frequencies. We say that the string resonates at
these frequencies and such modes are produced at resonance. At frequencies
far away from resonant frequencies, the oscillation of the string is small.
At resonance.
Oscillation mode is the first harmonic (the fundamental mode).