3 What have I learned about light?

Summary: Tags: science oxford-science student-book-7 physics Created: 2026-05-19 Last Updated: 2026-05-19

In this chapter, you have:

• learned that sources of Light and luminous objects emit (give out) light
• explored how light can be transmitted, reflected, or refracted
• studied the law of reflection and how we can see ourselves in a plane mirror
• discovered how our eyes detect light and send a signal to the brain
• learned that white light is made up of different colours, and that the colour of an object depends on the colours the object absorbs and reflects
• understood that filters absorb different colours and can change the way an object looks.

Journey through light What do I already know? - Day and night

• Light and shadows This chapter - 3.1 Light
• 3.2 Reflection
• 3.3 Refraction
• 3.4 The eye and the camera
• 3.5 Colour What comes next? - Wave properties
• Reflection and refraction
• Light and colour
• The electromagnetic spectrum

Figure 1

1. Match the words to the definitions. diffuse reflection ray hitting mirror specular reflection reflection off a rough surface incident ray reflection off a smooth surface reflected ray ray leaving mirror (4 marks)
2. Complete the sentences with the words. apertureCCD devicelens The retina of the eye is like the blank in a camera.The lens of the eye is like the blank in a camera.The pupil of the eye is like the blank in a camera. (3 marks)
3. A hunter wants to spear a fish. Explain why they aim at a place above where they see the fish. (2 marks)Explain why diving birds dive straight down to catch fish. (2 marks)
4. An actor is wearing a blue jacket and red trousers. Explain what the audience would see if the actor stood on stage in: white light (2 marks)green light (2 marks)
5. A student collects data about different types of plastic block. They measure the mass and the angle of refraction of a ray of light going into the block. Each block is the same size. Table 1 shows the results. Table 1Mass of block in g Angle of refraction in ° 250 27 220 32 275 24 300 21 State one variable that the student must keep the same during the investigation. (1 mark)Name the dependent variable. (1 mark)Name the independent variable. (1 mark) Describe the relationship between the mass of the block and the angle of refraction. (1 mark)
6. Copy and complete Figure 1 to show what happens when light travels through a lens. (4 marks) Figure 1
7. Light travels at 300 000 km/s in air. It slows down to 200 000 km/s in glass and to 226 000 km/s in water. A ray of light enters each medium with an angle of incidence of 40°. State and explain whether the angle of refraction would be bigger or smaller in water than in glass. (3 marks)
8. The Sun is 8.3 light-minutes away, which is 150 000 000 (150 million) km. The Moon is about 1.3 light-seconds away. Use these data and ratios to estimate the distance to the Moon in km. (4 marks)