Question on: JAMB Physics - 2023

Given:
- Amplitude (\(A\)) = 0.8 m
- Frequency (\(f\)) = 16 Hz
- Wave speed (\(v\)) = 20 \(m/s\)

First, calculate the wavelength (\(\lambda\)) using the formula \(v = f\lambda\):

\[ \lambda = \frac{v}{f} = \frac{20 \, \text{m/s}}{16 \, \text{Hz}} = 1.25 \, \text{m} \]

Then, calculate the wave number (\(k\)) using the formula \(k = \frac{2\pi}{\lambda}\):

\[ k = \frac{2 \pi}{1.25} \approx 5 \, \text{m}^{-1} \]

Therefore, the correct answer is 5 (to 1 significant figure)