In the chapter sound there is a sub division called quality .In this topic how will we know which wave form is for which musical instrument or how will we know the difference between the qualities of the wave forms given
Sounds may be generally characterized by pitch, loudness, and quality. Sound "quality" or "timbre" describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Timbre is then a general term for the distinguishable characteristics of a tone. Timbre is mainly determined by the harmonic content of a sound and the dynamic characteristics of the sound such as vibrato and the attack-decay envelope of the sound.
By clicking on any of the above links you can read more in detail about the quality or timbre of sound.
From the waveforms you cannot distinguish between the quality of the sound if they have the same frequency and amplitude.