Waves

Which of these properties is the same for all electromagnetic waves?

Link each type of electromagnetic wave with its use.

A scanner uses one type of wave to produce an image of a broken wrist. The type of wave emitted by the scanner is

An image of the bone is seen because the waves from the scanner are

Name one type of wave that is used in cancer treatment and explain what it does during the treatment.

Gamma radiation is used in hospitals even though it can be dangerous. Explain the risks to patients and doctors of using gamma radiation.

State one way of reducing the risks to a doctor who uses gamma radiation.

He uses a spring to demonstrate longitudinal waves.

Show (on paper) the directions in which the teacher moves his hand.

Give an example of a longitudinal wave.

The teacher fixes a vertical rod in a pond and places a small wooden ring on the rod. The ring floats on the water and moves up and down the rod as waves go past.

Show (on paper) a line for one wavelength, labelled W.

The distance from P to Q is 5.0 cm. Determine the amplitude of the wave.

The wooden ring reaches point P every 15 s. Calculate the frequency of the wave. Give the unit.

Explain how the movement of the wooden ring demonstrates that this wave is transverse.

The wave shown is a water wave. Give a different example of a transverse wave.

The diagram shows the side view of a wave on the surface of water. Each square on the grid represents 1 cm × 1 cm.

State the wavelength of the wave shown.

Sketch (on paper) the trace of a wave travelling at the same speed, but with a larger amplitude and a lower frequency.

State the equation linking wave speed, frequency and wavelength.

The speed of radio waves is 300 000 000 m/s. A radio wave has a frequency of 31 MHz. Calculate the wavelength of this radio wave.

A sound wave and a radio wave have the same wavelength. State why they have different frequencies.

Which letter represents the wavelength?

Which letter represents the amplitude?

A student writes some sentences about electromagnetic waves. His teacher circles a mistake in each sentence. Write a suitable correction for each mistake. The first one has been done for you.

He takes notes, but some of his notes are wrong. Is each statement right or wrong? (The first one, “the angle of incidence equals the angle of reflection”, is right.)

Jewellers cut jewels so that total internal reflection is more likely. Light enters a jewel along the normal AB and leaves along the normal CD. Between B and C there are two total internal reflections.

Complete the path of the light through the jewel (on paper).

Show, by calculation, that the critical angle for a refractive index of 1.5 is about 42°.

Explain why the quantity called refractive index has no unit.

The graph shows how critical angle varies with refractive index.

On a sketch, add the point (1.5, 42°) to the graph.

How can you tell that the point (1.5, 42°) is not anomalous?

The effect shown in the diagram is

State two ways in which the light waves change as they pass into the glass.

Which statement about sound waves is correct?

A microphone is connected to a data logger, which displays each sound wave as a graph. The graphs have the same scales. Horizontally, 1 square = 0.001 s.

The amplitude of sound wave Q is

The frequency of sound wave P is 250 Hz. Find the time period of sound wave P.

Find the frequency of sound wave Q.

Two students investigate the speed of sound in air. They use a stopwatch that shows times to the nearest 0.1 s, and a straight 100 m running track as their measure of distance. Describe what else they must do to obtain a value for the speed of sound.