RP9: Light

Question 1

What is the aim of this experiment?

Answer 1

• Investigate the reflection of light by different types of surfaces and the refraction of light by
  different substances.

Question 2

Describe how we can investigation the reflection and refraction of light by different surfaces/substances (method)

Answer 2

1. Slot the collimating slit into the ray box and turn on, producing a narrow ray of light.
2. Place the first block of material on top of a piece of paper. Trace around the block
   using a pencil.
3. Draw a normal to the block (a line at 90° to the surface of the block). Align the
   incident ray of light with the meeting point between the normal and the surface of the
   block.
4. Draw the reflected ray and refracted ray, as shown in the diagram below. Remove
   the block and draw a straight line between the point of reflection and the refracted
   ray on the other side of the block.
5. Using the protractor, measure:
   a. The angle of incidence - The angle between the incident ray and the normal.
   b. The angle of reflection - The angle between the reflected ray and the normal.
   c. The angle of refraction - The angle within the material between the normal
   and the refracted ray.
6. Repeat the experiment, using a new piece of paper for each different material of
   block

Question 3

List some safety precautions

Answer 3

• Don’t handle the ray box, as it will heat up during use.
• Take care carrying the blocks of material (especially glass).
• The room will be darkened, so the rays are clearly visible. Take care in your
  surroundings.

Question 4

What tool should be used to help draw the normal line on the sheet of paper?

Answer 4

• A set square or protractor to ensure that the angle is at a right angle to the main line?

Question 5

What conditions are needed for this experiment?

Answer 5

• Low lighting is needed so that the rays are visible

Question 6

What three angles should you measure after you have marked the lines on the paper?

Answer 6

• Angle of incidence
• Angle of reflection
• Angle of refraction

Question 7

How do you draw the refracted ray?

Answer 7

• Connect the point where the ray entered the bock and the point where the ray left the block on the other side with a straight line

Question 8

What does theory suggest about the angle of refraction for different materials?

Answer 8

• It should be different for each material depending on its refractive index

Question 9

What does theory suggest about the angle of incidence, and reflection?

Answer 9

• The angle of incidence should be the same as the angle of reflection