3 1 general properties of waves

Amplitude is the distance from the undisturbed position to the peak or trough of a wave.

Wavelength is the distance from one point on the wave to the same point on the next wave.

Frequency is the number of waves passing a point in a second.

Wave speed is the speed at which a wave travels.

A wavefront is a way of picturing waves as if from above, where each wavefront represents the peak of a single wave.

A ripple tank is used to demonstrate wave motion.

The symbol used for amplitude is .

The units of amplitude are metres (m).

Amplitude and wavelength drawn on a diagram of a transverse wave look like this:

The wave property indicated by the arrow on the diagram is time period.

The units of wave speed are metres per second (m/s).

The symbol for wave speed is .

False. The symbol for frequency is .

True. The units of frequency are hertz (Hz)

The units for wavelength are metres (m).

The symbol for wavelength is .

The wave equation in terms of wave speed is Where:

False. The wave speed equation in terms of wavelength is Where:

True. The wave speed equation in terms of frequency is Where:

The equation linking time period, and frequency, is:

Where:

A transverse wave is a wave where the oscillations are at right angles (perpendicular) to the direction of energy transfer.

Examples of transverse waves include:

A longitudinal wave is a wave where the oscillations are parallel to the direction of energy transfer.

Examples of longitudinal waves are:

False. Longitudinal waves require a medium to travel through, so they cannot travel in a vacuum since there are no particles in a vacuum.

In a longitudinal wave, the area where the particles are close together is called a compression.

In a longitudinal wave, the area where the particles are spaced far apart is called a rarefaction.

True. Visible light is part of the electromagnetic spectrum. All electromagnetic waves are transverse waves.

True. Electromagnetic waves are transverse waves and they can travel through a vacuum. However, other types of transverse waves such as water waves and S-waves are mechanical waves that require a medium.

The key difference between transverse and longitudinal waves is the direction of the vibrations with respect to the direction of the energy transfer. For transverse waves, the vibrations are perpendicular to the direction of energy transfer, while for longitudinal waves, the vibrations are parallel to the direction of energy transfer.

True. The highest point above the rest position of a transverse wave is called the peak or the crest of the wave.

The name of the lowest point below the rest position of a transverse wave is the trough.

The wave shown is a transverse wave because it oscillates at right angles of the direction of wave motion.

A correctly labelled longitudinal wave is as follows:

Reflection occurs when a wave meets a boundary between two media and does not pass through, but instead stays in the original medium.

The law of reflection states that the angle of incidence is equal to the angle of reflection.

Refraction occurs when a wave passes a boundary between two different transparent media and undergoes a change in speed causing it to change direction.

Diffraction is when waves pass around an obstacle or through a narrow gap, and the waves spread out.

False. Diffraction is greatest when the gap the wave is passing through is of a similar size to the wavelength of the wave. If the wavelength is much greater than, or much smaller than the gap then no diffraction will occur.

False. The angle of incidence is measured between the incident ray and the normal.

False. The angle of reflection is measured between the reflected ray and the normal.

Reflection is when a wave stays in the same medium, while refraction is when a wave passes into a different medium and changes speed.

False. The law of reflection states that the angle of incidence is equal to the angle of reflection. In refraction, the angle of refraction is dependent upon the angle of incidence and the media through which the wave travels.

The angle of refraction is measured with a protractor between the refracted ray and the normal.

A ripple tank can be used to demonstrate the following types of wave behaviour:

True. The amount of diffraction depends on the size of the gap compared to the wavelength of the wave.

When the frequency of water waves in a ripple tank is reduced, the wavelength increases.

You decrease the wavelength of the waves in a ripple tank by increasing the frequency of the waves.