The frequency of vibration of a string depends upon the tension of the string and the mass per unit length of the string. Which of the following options correctly represents the relationship between frequency, tension, and mass per unit length?
1) Frequency ∠ Tension × Mass per unit length
2) Frequency ∠ Tension ÷ Mass per unit length
3) Frequency ∠ Tension + Mass per unit length
4) Frequency ∠ Tension - Mass per unit length
