Light And Sound
Overview
A straw looks broken where it enters a glass of water. A shout comes back off a distant wall a moment after you make it. A single strand of glass thinner than a hair carries a television channel across an ocean. All three are the same two ideas at work: waves bounce, and waves bend.
This lesson takes reflection and refraction from the ray box on the bench to the fibre under the sea. You will learn the law of reflection, investigate refraction through three different shapes of block, meet the critical angle, and see why sound behaves in exactly the same two ways as light.
Objectives
- Know that light waves can be reflected and refracted
- Use the law of reflection (the angle of incidence equals the angle of reflection)
- Investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms
- Describe the role of total internal reflection in transmitting information along optical fibres and in prisms
- Explain what is meant by critical angle
- Know that sound waves can be reflected and refracted
Mind map
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Flashcards
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Light And Sound. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- The law of reflection states that: A) the angle of incidence is twice the angle of reflection B) the angle of incidence equals the angle of reflection C) the angle of reflection is measured from the surface D) the angle of reflection is always 90 degrees Answer: B
- A ray of light passes from air into glass. It bends: A) away from the normal B) towards the normal C) not at all D) back along its original path Answer: B
- Total internal reflection can occur when light travels: A) from air into glass at any angle B) from glass into air below the critical angle C) from glass into air above the critical angle D) from air into glass above the critical angle Answer: C
- A ray of light strikes a mirror at 20 degrees to the mirror surface. The angle of reflection measured from the normal is: A) 20 degrees B) 40 degrees C) 70 degrees D) 90 degrees Answer: C
- A ray enters a semi-circular block aimed at the centre of the flat face. At the curved surface it: A) bends towards the normal B) bends away from the normal C) does not bend, because it travels along the normal D) is totally internally reflected Answer: C
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Practice Mock Questions
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