SNC2DDate: ______

Chapter 11 &12 Test Review Questions

  1. Light bends toward the normal when going from material A into material B. Compare the speed of light in the two materials. Which is the faster medium?

Material b has a slower speed of light, therefore medium A is the faster.

  1. Four materials have indices of refraction of 1.72, 1.00, 2.30, and 1.50. Which material will refract light the most? Why?

2.30 will refract light the most because it will slow light down the most

  1. Complete the following ray diagrams:

a)A ray of light has an angle of incidence of 30 to the normal when it goes through a piece of glass. Draw the approximate path of light as it passes out of the glass. / b)A ray of light has an angle of refraction of 44 in air. Draw the approximate refracted ray through the plastic.
  1. If a bundle of parallel incident rays undergoing diffuse reflection follow the law of reflection, then why do they scatter in many different directions after reflecting off a surface?

Because they are all hitting the surface at different angles to each other since the surface is rough.

5. Draw the refracted ray for each of the incident rays shown as they enter the medium, and when the leave the medium. The medium is glass (ie. more optically dense than air).

  1. a) What is the Law of Reflection?

The angle of incidence is equal to the angle of reflection

b) A light ray has an angle of incidence of 67o. The reflected ray would make what angle with the reflecting surface?

23o

  1. Emergency vehicles such as ambulances are often labeled on the front hood with reversed lettering (e.g., ECNALUBMA). Explain why this is so.

In plane mirrors, light undergoes lateral inversion where the image appears flipped sideways compared to the object.

  1. If a toddler crawls towards a mirror at a rate of 0.25 m/s, then at what speed will the toddler and the toddler's image approach each other?

0.50m/s

In one second, the toddler has moved towards the mirror by a distance of 0.25 meters. In the same second, the image will be 0.25 meters closer as well. Thus, the toddler and its image have become 0.50 meters closer in 1 second.

  1. The diagram below shows an object located at C. Describe the image formed by this object using a ray diagram and S.A.L.T..
  1. A certain substance has a critical angle of 24.5˚. What minimum angle of incidence, to the nearest tenth of a degree, will result in total internal reflection?

24.6˚

  1. A beam of light is traveling from air into glass. Would refraction still occur if light traveled at the same speed in air and in glass? Explain.

NO there would be no change in speed

  1. Why are right-angled prisms used to make periscopes instead of mirrors?

Because they will not deteriorate over time like the backing of a mirror would.

  1. The speed of light in carbon disulfide is 1.84 x 108 m/s. Calculate the index of refraction for carbon disulfide.

1.63

  1. The index of refraction for heavy flint class is 1.65. What is the speed of light in this medium?

1.82 x 108 m/s

  1. Look at the indices of refraction in the table below:

Medium / Index of Refraction
A / 2.30
B / 1.76
C / 1.98

Through which medium does light pass:

a)Fastest? Medium B

b)Slowest? ? Medium A

  1. Describe 3 properties of Light.

Travels in straight lines, does not need a medium to travel, and is composed of waves

  1. Describe how each of the following produce light:
  1. Incandescence – light is the result of high temperatures
  2. Electric Discharge – passing electricity through a gas
  3. Phosphorescence – absorbing UV light which results in emitting visible light over an extended period of time
  4. Fluorescence – immediate emission of light as the result of absorption of UV
  5. Chemiluminescence – light as a result of a chemical reaction with little or no heat produced
  6. Bioluminescence – light in living organisms via a chemical reaction with little or no heat produced
  7. Triboluminescence – light from friction as a result of scratching, crushing or rubbing certain crystals
  1. What does it mean if something is Luminous? What about Non-Luminous?

Luminous – can produce its own light

Non-luminous – does not produce own light and can only be seen by using reflected light.