A Level Physics Practice Exam

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Study for the A Level Physics Exam. Our quiz features flashcards and multiple choice questions, each with hints and explanations. Prepare thoroughly!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

What is the equation to find the frequency of the nth harmonic on a stationary wave?

f = n * L
f = (n * c) / 2L
f = 2L / n
f = c / (n * L)

The correct answer is: f = (n * c) / 2L

The fourth choice, which provides the equation $ f = \frac{n \cdot c}{2L} $, is correct for finding the frequency of the nth harmonic on a stationary wave. In this equation, $ f $ represents the frequency of the harmonic, $ n $ is the harmonic number (1 for the fundamental frequency, 2 for the first overtone, etc.), $ c $ is the speed of the wave, and $ L $ is the length of the vibrating medium or the cord. The reasoning behind this formula is based on the relationship between the wavelength, frequency, and wave speed. For a wave in a stationary medium, the wavelength for the nth harmonic is given by $ \lambda = \frac{2L}{n} $. Knowing that the wave speed can be expressed as $ c = f \lambda $, substituting for the wavelength leads us to derive the frequency formula. Thus, the equation concisely relates all necessary quantities, providing a clear method to calculate the frequency of any specific harmonic in a stationary wave setup.