MCQ Solution: Oscillations
A guitar string oscillates with a fundamental frequency of 200 Hz. What is the fundamental frequency if you increase the mass per unit length of this string by a factor of 4 while keeping the tension constant?
1) 50 Hz
2) 100 Hz
3) 200 Hz
4) 400 Hz
The fundamental frequency is f0=v/2L. The speed of the waves, in turn, is given by v = Ö[T/(m/L)]. When we increase m/L by a factor of 4, we therefore decrease v by a factor of two.