The length of the string of a musical instrument is 90   cm and has a fundamental frequency of 120   Hz . Where should it be pressed to produce fundamental frequency of 180   Hz ?

Step-by-step solution

The fundamental frequency in terms of speed of wave and length between two boundaries, ν = v 2 l , it means. ν 1 ν 2 = l 2 l 1 ⇒ l 2 = l 1 ν 1 ν 2 = 90 × 120 180 = 60   cm