Английский язык. Ч.3 (Units 9,10). Ильичева Н.А - 15 стр.

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13. Read the text again and do the following.
   1. State the law of reflection and distinguish between regular and diffuse
      reflections.
   2. Explain the principles of refraction and total internal reflection.
   3. Explain how light is reflected from spherical mirrors.
   4. Explain what is meant by dispersion of light and explain why it occurs.
   5. Discuss the difference between sound waves and visible light waves.


Follow-up activities


14. Your friend, a girl 1.60 m tall wants to buy a mirror but she doesn’t
know how tall it must be and how high its lower edge must be above the
floor so as to be able to see her whole reflection. Assume her eyes are 10 cm
below the top of her head. Explain to her how to find it out. Then use the
words from the list to fill in the gaps in the given answer.
   Height, reflection, bottom, edge, to reach, ray, half, equals, to extend.


   I’ve decided to diagram the situation for you to understand it better. First,
consider the a) … from your foot, AB. Upon b) … it becomes BE and enters
your eye E. The light from your foot (point A) enters your eye after reflecting at
B; so the mirror needs c) … no lower than B. Because the angle of reflection
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