Across
- 2. optical device for viewing distant objects ;there are two types:reflecting and refracting telescopes
- 6. piece of transparent material that is thinner in the middle than at the edges; light rays passing through it diverge or spread out
- 10. describes objects that produce light; for example, the sun, light bulb, fire, etc
- 11. angle of incidence of a wave hitting a surface equals the angle of reflection
- 14. reflection reflection that happens when parallel rays hit a rough surface; all rays reflect at different angles
- 15. line perpendicular to a surface (that is, forms a 90˚ angle with the surface)
- 16. angle between the incident ray and the normal
- 18. refers to the whole range of wavelengths of visible and invisible electromagnetic radiation
- 20. device for viewing distant objects;made up of two short refracting telescopes fitted together
- 21. acronym for radio detection and ranging; system that detects reflected microwaves
- 24. curved piece of glass or other transparent material that refracts light in a predictable way
- 25. flat mirror; reflecting surface that has no curvature
- 26. angle between the reflected ray and the normal
- 27. any device that uses light; for example,mirrors,lenses,microscopes,and telescopes
- 29. model used to explain the characteristics and behaviour of light energy; it describes light as energy in the form of waves; the different colours of light have different wavelengths; waves with shorter wavelengths have higher energy than those with longer wavelengths
- 30. CROSSWORD
Down
- 1. bending of light as it travels from one material to another material
- 3. point at which light rays meet, or appear to meet, after being reflected by a mirror, or refracted by a lens
- 4. piece of transparent material that is thicker in the middle than at the edges; light rays passing through it converge or come together
- 5. reflecting surface that bulges out like the back of a spoon; light rays reflected from it diverge (spread out)
- 7. all forms of radiant energy: visible light, infrared radiation,ultraviolet radiation, radio waves, X-rays etc.
- 8. reflection that happens when parallel rays hit a smooth surface; all rays reflect at the same angle
- 9. describes objects that do not produce light but may reflect it (for example, the moon); most objects on earth are non-luminous
- 12. telescope that uses a curved mirror and a lens to form an enlarged image
- 13. brightness of light;amount of light arriving per unit area at a place
- 17. telescope that uses two lenses to form an enlarged image
- 19. describes materials that allow light to pass through with little or no reflection; for example, glass
- 22. ray of light that arrives at a mirror or other substance
- 23. describes materials that allow some light to pass through
- 28. image formed when rays meet at a point; the image can be projected onto a screen