Figure 1 shows a longitudinal wave - AQA - GCSE Physics Combined Science - Question 1 - 2022 - Paper 2

The frequency of the wave is given as 4.0 kHz.

First, convert the frequency into Hertz: 4.0 kHz = 4000 Hz.

The period (T) can be calculated using the formula:

$T = \frac{1}{f}$

Substituting the value of frequency, we have:

$T = \frac{1}{4000} = 0.00025 \text{ seconds (s)}$

The equation that links frequency, wavelength, and wave speed is:

$v = f \times \lambda$

To find the wavelength, we need to use the speed of sound at 28 °C. From Figure 2, the speed of sound at 28 °C is approximately 348 m/s.

Now, using the equation:

$v = f \times \lambda$

We rearrange to find wavelength:

$\lambda = \frac{v}{f}$

Substituting the known values: $\lambda = \frac{348}{300}$ $\lambda \approx 1.16 \text{ m}$