Question 3

This question is about waves.

A diagram of a water wave shows a toy duck floating on the surface of a pond. The duck moves up and down as the waves pass underneath it.

On the diagram, the distance between two consecutive wave crests (the wavelength) is measured to be $5.0\text{ cm}$. The scale of the diagram is 1:40 (where $1\text{ cm}$ on the diagram represents $40\text{ cm}$ in real life). Calculate the real wavelength of the water waves in centimetres.

State the equation linking wave speed, frequency, and wavelength.

The frequency of the water waves is $2.5\text{ Hz}$. Calculate the speed of the water waves in metres per second ($\text{m/s}$).

Water waves are transverse. State another example of a transverse wave.

The diagram below shows plane water waves passing through a gap in a barrier, with a toy duck located in a calm area of water to the side.

A diagram showing plane (straight) wave fronts approaching a barrier from the top. The barrier has a single gap in the center. After passing through the gap, the wave fronts become curved, spreading outwards into the region behind the barrier. A small toy duck is situated to the left of the gap, behind the barrier, in the path of these spreading curved waves.

State the wave phenomenon that causes the waves to spread out as they pass through the gap.

Discuss how changing the width of the gap would affect the movement of the toy duck.