Concepts Of Physics MCQ Edition [Volume 1]PhysicsWave Motion and Waves on a String
A travelling wave is passing along a string in the positive x -direction with a wave speed of 20 cm s ⁻¹ . The transverse displacements of the particles of the string at t = 0 are plotted in the associated figure. Determine the frequency of the wave.
Options
- A5 Hz
- B10 Hz
- C2.5 Hz
- D80 Hz
Correct answer
D. 80 Hz
Step-by-step solution
From the given graph, the wavelength is the distance over which the wave pattern repeats. Observing the x -axis, one complete cycle of the wave spans from x = 0 to x = 4 cm . Therefore, the wavelength = 4 cm . The wave number k is defined as: k = 2 Substituting the value of : k = 2 4 = 2 cm ⁻¹ Using 3.14 : k 3.14 2 = 1.57 cm ⁻¹ Rounding to one decimal place, we get 1.6 cm ⁻¹ .