Reflection and refraction of waves

Figure 1 shows a ray of light incident on a mirror.

Draw the reflected ray on Figure 1.

On Figure 1, label the angle of incidence with the letter i and the angle of reflection with the letter r.

A lens has a focal length of 17 cm.

Calculate the power of the lens in dioptres.

Use the equation

power =_........ dioptres

Which of these is the best reason for explaining why a leaf appears green in daylight?

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

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Figure 2

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

Figure 3 shows the results in a table.

Figure 4 shows a graph of these results.

The two shaded rows in Figure 3 are not plotted on the graph in Figure 4.

Plot these missing results on the graph in Figure 4.

Draw a curve of best fit through the points on the graph in Figure 4.

Using Figure 4, 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 9 is a table of data for three coloured beams of light travelling from air into glass.

Using data from Figure 9,

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 =_........

Describe how the power of a lens is related to its focal length and the shape of the lens.

Give one example of a virtual image that a lens could produce.

Give one example of a real image that a lens could produce.

A student investigates what happens when a ray of light shines into a semicircular block made of transparent plastic.

The ray meets the straight edge at an angle of 20°, as shown in Figure 13.

The student gradually increases the angle at the straight edge from 20° to 50° and observes what happens to the ray of light.

The critical angle for the transparent plastic is 38°.

Describe what you would expect to happen to the ray of light as the angle at the straight edge increases from 20° to 50°.

You may add to the diagram in Figure 13 to help your answer.

The asteroid Ceres orbits the Sun between Mars and Jupiter.

During its orbit, Ceres receives electromagnetic radiation from the Sun.

The average temperature of Ceres is constant.

Explain why the average temperature of Ceres remains constant.

A flag has three colours in daylight.

The flag is taken into a dark room.

Figure 3 shows the flag when a torch shines white light on to the flag.

Figure 4 shows the same flag when the torch is covered with a coloured filter.

State the colour of the filter that has covered the torch.

A student uses a converging lens to produce an image of a tree on a screen.

The image of the tree on the screen is shown in Figure 5.

The student is asked to describe the image of the tree.

The student’s descriptions are shown in the table.

The first description is correct, the image is upside down.

Complete the table by adding the correct descriptions of the image.

A student uses a ray box to investigate two lenses, P and Q.

Figure 6 shows the student’s drawings of rays of light before and after passing through the lenses.

Complete the following sentences.

The focal length of lens P is_........ than the focal length of lens Q.

The power of lens P is_........ than the power of lens Q.

Figure 7 shows light reflecting from two mirrors in a bathroom.

Mirror R has a dry surface.

Mirror S has lots of small drops of water on the surface.

A person looks into each mirror.

Explain the difference between the image seen in mirror R and the image seen in mirror S.

The law of reflection of light applies to reflections from

A student uses a mirror to demonstrate that the angle of incidence is equal to the angle of reflection.

Figure 8 shows the apparatus the student uses.

Describe the procedure the student should use with the ray and mirror in the position shown in Figure 8.

You should include any extra equipment needed.

You may add to Figure 8 to help your answer.

Figure 9 shows a ray of light from a ray box passing through a semi-circular glass block.

A student uses the apparatus in Figure 9 to determine the critical angle for glass.

State why the ray of light does not change direction as it enters the glass block at X.

Describe how the critical angle for glass can be determined using the apparatus shown in Figure 9.

Figure 10 shows a ray diagram of the virtual image produced by a diverging lens.

State what is meant by the term virtual image.

Which row of the table shows two transverse waves?

Figure 16 is an energy diagram for a sound wave incident on a sound-insulating board.

sound-insulating

The incident energy is 0.25 J.

The absorbed energy is 67 % of the incident energy.

The reflected energy is 15 % of the incident energy.

Calculate the amount of the transmitted energy.

Give one way to reduce the percentage of energy transmitted through the sound-insulating board.

The ratio of the absorbed energy E_a to incident energy E_i is the coefficient of absorption of sound α.

The table in Figure 17 gives the coefficient of absorption for various materials.

Explain why rooms with carpets and curtains are less noisy than rooms without them.

Use the information given in Figure 17 in your answer.

* (d) Explain how sound waves can be used to determine the depth of the ocean directly underneath a boat.

You may draw a diagram to help with your answer.

Figure 3 shows a ray of light striking a mirror.

The angle of incidence is 30˚ and the ray of light is reflected.

The angle of reflection is the angle between

Figure 4 shows two lenses, P and Q, arranged to form a simple telescope.

State one use for a telescope.

Which of these describes the lenses?

The focal length of lens Q is 0.14 m.

Calculate the power of the lens.

Use the equation

power of lens =_........ dioptre

A student is in a laboratory that has windows.

The student is given a converging lens, and a sheet of paper.

Describe how the student can produce an image of the window frame on the sheet of paper.

Figure 9 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 10 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 10.

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 does an experiment to determine the critical angle for glass.

The student shines a ray of light into a semicircular glass block and measures the angles i and r, as shown in Figure 14.

The ray of light does not change direction when it enters the glass block at point X.

Which of these explains why the ray of light does not change direction when it enters the glass block at point X.

The student repeats the procedure for different values of angle i.

Figure 15 is a graph of the student’s results.

Describe how the student should use the graph in Figure 15 to determine the critical angle for glass.

Figure 16 shows two iron spheres, P and Q, near to a radiant heater. P is painted black and Q is painted white.

Each sphere is the same distance away from the heater.

The spheres have the same radius.

The heater is switched on and the spheres heat up.

The temperature of each sphere is monitored.

Explain why the temperature of sphere P increases at a faster rate than the temperature of sphere Q.

The heater remains switched on.

Figure 17 shows how the temperature of sphere P changes with time.

Explain why the temperature of P reaches a constant value, even though the heater remains switched on.

This question is about reflection and refraction of light.

Figure 4 shows a ray of light travelling to a plane mirror.

On Figure 4, draw the ray of light after it reflects off the mirror surface.

Figure 5 shows a ray of light in air travelling to a glass block.

On Figure 5, draw the ray of light after it refracts at the surface of the glass block.

Figure 6 shows a ray of light in water, travelling to the surface of the water.

The angle marked X is greater than the critical angle.

On Figure 6, draw the ray of light after it reaches the surface of the water.

A converging lens has a focal length of 40 cm.

Calculate the power of this lens in dioptres.

Use the equation

power of the lens =_........ dioptres

Which ray diagram shows total internal reflection at an air and glass boundary?

Figure 1 is a ray diagram for a converging lens when used as a magnifying glass.

Using information from Figure 1, determine the magnification of the virtual image.

Use the equation

Describe one way the magnification of the image could be increased.

Figure 2 shows a converging lens used to produce a real image on a screen.

The apparatus is used to find the focal length, f, of the lens.

The screen is moved to give a clear image of the object.

The distance from the object to the lens, a = 20 cm.

The distance from the image to the lens, b = 40 cm.

Calculate the focal length, f, of the lens.

Use the equation

The human ear can only detect frequencies below ultrasound and above infrasound.

Which of these gives the approximate range of frequencies for the human ear?

Suggest two reasons why there are limits to the frequencies that a human ear can detect.

Ultrasound can be used to find cracks in metals.

Figure 13a shows the signals emitted and received when the metal bar has no cracks.

Figure 13b shows the signals emitted and received when the metal bar has a crack.

Explain how the signals in Figure 13a and Figure 13b show that there is a crack in the metal bar in Figure 13b.

Suggest one reason why the amplitude of signal R in Figure 13b is smaller than the amplitude of signal P shown in Figure 13a.

This question is about light.

White light includes all the colours in the visible spectrum.

A beam of white light is the only light that shines on a book. The book appears green. A red filter is placed between the source of white light and the book.

What colour does the book appear now?

Figure 8 shows a shiny metal ball.

A clear image of a building can be seen on the surface of the ball.

This clear image is an example of

Explain why the surface of the metal ball gives a clear image. You may draw diagrams to help with your answer.

Figure 9a and Figure 9b show rays of light before and after passing through different lenses.

State one similarity and one difference in the way the rays of light pass through the lenses.

Figure 10 shows two glass lenses P and Q.

State how the power of P is different from the power of Q.

*(d) Figure 11a shows refraction of light at a boundary between glass and air. Figure 11b shows total internal reflection of light at a boundary between glass

Use Figure 11a and Figure 11b to explain refraction and total internal reflection.

You may add to Figure 11a and Figure 11b to help with your answer.

A student is investigating the refraction of light.

Figure 5 shows part of the apparatus and the angles to be measured.

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

Figure 6 shows the student’s results.

On the graph in Figure 6, draw the best fit curve.

Use the graph in Figure 6 to estimate the value of angle r when angle i is 80°.

Describe how angle r changes with angle i for the results shown on the graph in Figure 6.

In Figure 5, 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 7, 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 7 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 =_........

To investigate refraction in a rectangular glass block a student uses the apparatus shown in Figure 5.

Describe how the student should measure the angle of refraction.

Figure 6 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 6.

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

Which lens is a converging lens with the greatest power?

The equation that relates the power of a lens to the focal length of the lens is

The power of a lens is 5 dioptres.

Use the equation to calculate the focal length of the lens in cm.

Figure 3 shows a semicircular glass block.

Figure 3

Describe how a student could use the semicircular glass block and other apparatus to determine the critical angle for a glass‑air boundary.

You should add to the diagram in Figure 3 to help with your answer.

A long time ago, scientists believed that the Earth was at the centre of the Solar System.

Evidence has since proved that the Sun is at the centre of the Solar System.

State one other idea about the Solar System that has changed over time.

Figure 4 shows data for some of the planets of the Solar System.

distance from the Sun in millions of km

Figure 4

Ceres is an asteroid that orbits the Sun between Mars and Jupiter. It takes Ceres 4.6 Earth years to make one orbit of the Sun.

Use the graph to estimate the distance of Ceres from the Sun.

Show your working.

distance of Ceres from the Sun =_........ millions of km

The diagram in Figure 7 shows two students, P and Q, trying to measure the speed of sound in air.

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

Explain one way the students could improve their method.

Figure 8 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 9 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 9 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 10 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 10 to calculate the speed of sound in warm air.

Give your answer to an appropriate number of significant figures.

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

Figure 15 shows some of the apparatus used in the investigation.

In Figure 15, angle Y is the angle of

Figure 16 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

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

Figure 2 shows some of the apparatus used in the investigation.

In Figure 2, angle Y is the angle of

Figure 3 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 × 10⁸ m/s.

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

Calculate the frequency of yellow light.

State the unit.

Use the equation

Figure 7 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 7.

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

Description 2

used in cooking

used in communication

typical wavelength 150 mm

Description 3

used in communication

produced by oscillations in electrical circuits

typical wavelength 150 m

Description 4

used in medical scanning

is emitted by the nucleus of an atom

typical wavelength 2.0 × 10⁻³ nm

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.