1. (a) Figure 1 shows part of a wave - Edexcel - GCSE Physics Combined Science - Question 1 - 2021 - Paper 1

The student can determine the frequency of the ripples by using the stopwatch to time how long it takes for a certain number of ripples to pass a fixed point. By counting the number of ripples and dividing it by the time taken, the frequency can be calculated. For example, if 10 ripples pass in 5 seconds, the frequency is given by:

$f = \frac{10 \text{ ripples}}{5 \text{ seconds}} = 2 \text{ Hz}$

Using the equation for wave speed given by:

$v = f \times \lambda$ where:

• $v$ is the speed of the wave (1.5 m/s),
• $f$ is the frequency (0.70 Hz), and
• $\lambda$ is the wavelength, we can rearrange the equation to solve for $\lambda$:

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

Substituting the known values:

$\lambda = \frac{1.5 \text{ m/s}}{0.70 \text{ Hz}} \approx 2.14 ext{ m}$

Thus, the wavelength of the wave is approximately 2.14 m.

Transverse waves are characterized by oscillations that occur perpendicular to the direction of wave travel. This means that as the wave moves forward, the particles of the medium move up and down. An example of this is water waves, where the surface of the water ripples up and down.

In contrast, longitudinal waves have oscillations that occur in the same direction as the wave travels. This results in areas of compression and rarefaction. Sound waves in air are a common example, where air molecules move back and forth in the direction of the wave movement.