Concepts Of Physics MCQ Edition [Volume 1]PhysicsWave Motion and Waves on a String
A string exhibits three resonant frequencies at 90 Hz , 150 Hz , and 210 Hz . Identify which harmonics of the fundamental frequency these given frequencies correspond to.
Options
- A3rd, 5th, and 7th
- B3rd, 6th, and 9th
- C1st, 2nd, and 3rd
- D2nd, 4th, and 6th
Correct answer
A. 3rd, 5th, and 7th
Step-by-step solution
The given resonant frequencies are 90 Hz , 150 Hz , and 210 Hz . The fundamental frequency f₀ is the highest common factor of the given resonant frequencies. f₀ = HCF (90, 150, 210) = 30 Hz Expressing the given frequencies in terms of f₀ : 90 Hz = 3 30 Hz = 3f₀ 150 Hz = 5 30 Hz = 5f₀ 210 Hz = 7 30 Hz = 7f₀ Therefore, the given frequencies correspond to the 3rd, 5th, and 7th harmonics.