Reflection & refraction of waves

Draw one straight line from each electromagnetic radiation to its correct description.

Different colours of light have different frequencies.

Which of these colours has the highest frequency?

Figure 1 is a diagram of a glass block being used to investigate the refraction of light.

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Figure 1

The angle of incidence was varied and the angle of refraction was measured each time.

Figure 2 shows the results in a table.

Figure 3 shows a graph of these results.

The two shaded rows in Figure 2 are not plotted on the graph in Figure 3.

Plot these missing results on the graph in Figure 3.

Draw a curve of best fit through the points on the graph in Figure 3.

Using figure 3, describe the relationship between the angle of refraction and the angle of incidence.

When light travels from air into glass, it is refracted.

To investigate this, a student has a rectangular glass block and a ray box.

The ray box produces a ray of light.

Describe how the student should use the glass block and ray box to produce a refracted ray and mark its position.

You may draw a diagram to help your answer.

Figure 6 is a table of data for three coloured beams of light travelling from air into glass.

Using data from Figure 6,

state what happens to the wavelength of light when the light travels from glass into air

state what happens to the frequency of light when the light travels from glass into air.

The speed of blue light in air is 3.0 × 10⁸m / s.

Calculate the change in the speed of blue light when it travels from air into glass.

Use the equation

v = f × λ

change in speed =_........

Figure 6 shows two technicians, L and M, measuring the speed of sound in air.

L fires a starting pistol.

M starts a stopwatch when first seeing the smoke from the starting pistol.

M stops the stopwatch when hearing the bang made by the starting pistol.

The distance between L and M is 120 m.

M’s reaction time is 0.23 s.

The speed of sound in air is 330 m / s.

Calculate M’s reaction time as a percentage of the time sound takes to travel from L to M.

_........ %

Which of these would improve the technicians’ measurement of the speed of sound?

Figure 7 shows the difference in refraction of sound waves and light waves when these waves travel from air into water.

Explain why the refraction of the sound wave is different from the refraction of the light wave in Figure 7.

Light is one example of an electromagnetic wave.

Light can transfer energy from a lamp to the leaf of a plant, causing chemical reactions in the leaf.

Describe examples of two other electromagnetic waves transferring energy.

A student is investigating the refraction of light.

Figure 4 shows part of the apparatus and the angles to be measured.

The student measures angle r for several different values of angle i.

Figure 5 shows the student’s results.

On the graph in Figure 5, draw the best fit curve.

Use the graph in Figure 5 to estimate the value of angle r when angle i is 80°.

angle r =_........ °

Describe how angle r changes with angle i for the results shown on the graph in Figure 5.

In Figure 4, the frequency of the light remains the same in glass as in air.

Which row of the table describes what happens to the wave velocity and to the wavelength of the light when the light travels from air to glass?

In Figure 6, only refraction of light is shown.

Other things happen to the light as it travels from P to Q.

The intensity (brightness) of the light at Q is less than the intensity of the light at P.

Explain the decrease in intensity as the light travels from P to Q.

You may add to Figure 6 to help your answer.

A radio station transmits on 97.4 MHz.

To receive the waves an aerial needs a length equal to half the wavelength of the radio waves being transmitted.

Calculate the length of the aerial needed.

The speed of the radio waves is 3.00 × 10⁸m / s.

length of aerial =_........ m

To investigate refraction in a rectangular glass block a student uses the apparatus shown in Figure 3.

Describe how the student should measure the angle of refraction.

Figure 4 is a simplified diagram to show radio waves from a transmitter moving upwards, then meeting a boundary between lower and upper layers of the atmosphere.

Explain what happens to the radio waves after they meet the boundary between the lower and upper layers as shown in Figure 4.

Your explanation should refer to changes in direction and speed of the waves.

The diagram in Figure 4 shows two students, P and Q, trying to measure the speed of sound in air.

P will clap his hands together.

When Q sees P clap his hands, she will start a timer.

When Q hears the clap, she will stop the timer.

Explain one way the students could improve their method.

Figure 5 shows a long metal rod and a hammer. The rod is hit at one end by the hammer. This causes a sound wave to travel along the inside of the metal rod.

Describe how hitting the rod causes a sound wave to travel along the inside of the rod.

Sound travels slower in air than it does in water.

Figure 6 shows the direction of travel of a sound wave approaching a boundary between air and water.

The sound wave refracts at the boundary between air and water.

Complete the diagram in Figure 6 to show the direction the sound wave travels in the air.

Sound travels slower in cold air than it does in warm air.

The equation relating the speed of sound in air to the density of the air is

The table in Figure 7 gives some data about the speed of sound in air and the density of air.

Use the equation and the data in the table in Figure 7 to calculate the speed of sound in warm air.

Give your answer to an appropriate number of significant figures.

speed of sound in warm air =_........ m/s

A student investigates what happens when light travels from air to glass.

Figure 8 shows some of the apparatus used in the investigation.

In Figure 8, angle Y is the angle of

Figure 9 is a graph of the student’s results.

Use the graph to calculate a value for

The student concludes that angle Y is directly proportional to angle X.

Explain what the student must do to test this conclusion in more detail.

The speed of light is 3.0 × 10⁸m/s.

The wavelength of yellow light is 5.8 × 10⁻⁷m.

Calculate the frequency of yellow light.

State the unit.

Use the equation

frequency =_........ unit_........

Give one colour of light that has a longer wavelength than yellow light.

Give one colour of light that has a higher frequency than yellow light.

A student investigates what happens when light travels from air to glass.

Figure 1 shows some of the apparatus used in the investigation.

In Figure 1, angle Y is the angle of

Figure 2 is a graph of the student’s results.

Use the graph to calculate a value for

The student concludes that angle Y is directly proportional to angle X.

Explain what the student must do to test this conclusion in more detail.

The speed of light is 3.0 × 10⁸m/s.

The wavelength of yellow light is 5.8 × 10⁻⁷m.

Calculate the frequency of yellow light.

State the unit.

Use the equation

frequency =_........ unit_........

Figure 5 shows a tuning fork.

When the prongs of the tuning fork are struck, the prongs vibrate in the directions shown by the arrows on Figure 5.

Describe how the vibrating tuning fork causes a sound wave to travel through the air.

You may add to the diagram if it helps your answer.

The following descriptions describe waves from different parts of the electromagnetic spectrum.

Complete each description by adding the name of the wave.

Use the name of each wave only once. Each description refers to a different part of the electromagnetic spectrum.

Description 1

used in cooking

used in short-range communication

typical wavelength 900 nm

name of wave_........

Description 2

used in cooking

used in communication

typical wavelength 150 mm

name of wave_........

Description 3

used in communication

produced by oscillations in electrical circuits

typical wavelength 150 m

name of wave_........

Description 4

used in medical scanning

is emitted by the nucleus of an atom

typical wavelength 2.0 × 10⁻³nm

name of wave_........

When white light crosses the boundary between air and glass, it can split up into the colours of the spectrum.

Explain, in terms of speed, why the light behaves like this.