Optics (Edexcel GCSE Physics)

A student is investigating the refraction of light.

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

Figure 5

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

Figure 6 shows the student’s results.

Figure 6

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

[1]

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

angle r = .............................................................° [1]

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

[2]

Higher Tier Only 

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.

Figure 7

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

You may add to Figure 7 to help your answer.

Higher Tier Only

Which of these sketch graphs represents the speed of light as it travels from P to Q?

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

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

Figure 2

i) In Figure 2, angle Y is the angle of

[1]

ii) Figure 3 is a graph of the student’s results.

Figure 3

Use the graph to calculate a value for

................................[2]

iii) 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.

[3]

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:

frequency = ........................ unit ..............

Figure 12 is a diagram showing a lens, with some light rays passing through it.

Figure 12

i) This diagram shows a 

 [1]

ii) Which length, labeled on Figure 12, shows the focal length of the lens?

☐ P    

☐ Q    

☐ R    

☐ S    

[1]

Calculate the power of a lens of focal length 17 cm. Use the equation

Give the answer to 2 significant figures.

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

More than two thousand years ago the Earth was believed to be at the centre of the universe as shown in Figure 13.

The planets, the Moon and the Sun were believed to be in orbit around the Earth.

In 1543 Nicolaus Copernicus proposed that the Earth was a planet, and that the Earth and the other planets orbit around the Sun.

                     This model is shown in Figure 14.

 Figure 13                            Figure 14

Discuss how evidence has changed our views of the universe.

Figure 3 shows a ray of light going from air to glass.

Fill in the labels in Figure 3 using words from the box. 

Figure 3

i) An astronomer observes light from a distant galaxy.

As the galaxy moves away from us, the spectrum of the light is 

 [1]

ii) The shift in the spectrum of light from the distant galaxy provides evidence for the expansion of the

[1]

The speed of sound in air is 300 m/s.

The speed of sound in water is 1500 m/s.

Calculate the ratio of the speed of sound in air to the speed of sound in water.

ratio of speed of sound in air to the speed of sound in water =..................

i) Which lens is a converging lens with the greatest power? 

[1]

ii) 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.  

[2]

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. 

i) 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.  

[1]

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

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 [3]

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.

Figure 8

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

i) This clear image is an example of

[1]

ii) Explain why the surface of the metal ball gives a clear image.

You may draw diagrams to help with your answer.

[2]

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

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

similarity...........................................................................

difference........................................................................

[2]

ii) Figure 10 shows two glass lenses P and Q.

Figure 10

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

[1]

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 and air.

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.