Required Practical 9 - Investigate the reflection and refraction of light by different substances

Question 1

Apparatus used to investigate the reflection and refraction of light by different substances:

Answer 1

• ray box
• lens and slit to produce a narrow ray of light

Question 2

Hazards when investigating the reflection by different types of surfaces and refraction of light by different types of substances:

Answer 2

• ray boxes get hot so important to switch them when not being used
• can also use laser - but can be more dangerous so ray box is safer

Question 3

What is important to do with ray boxes when they’re not being used?

Answer 3

ray boxes do get hot so it’s important to switch them off when they’re not being used

Question 4

Method to investigate the reflection and refraction of light by different substances:

Answer 4

1. Place glass block on piece of paper
2. Draw around glass block
3. Use ray box to shine ray of light through the glass block
4. Mark ray of light entering the glass block (incident ray)
5. Mark ray of light emerging from glass block
6. Join the points to show the path of the complete ray through the block
7. Draw a normal line at 90 degrees to the surface
8. Use a protractor to measure the angle of incidence
9. Use a protractor to measure the angle of refraction
10. Use a ray box to shine a ray of light at a range of different angles (of incidence)
11. Increase the angle of incidence in 10 degree intervals
12. From an angle of incidence of 10 degrees to angle of incidence of 70 degrees

Question 5

Results for investigating the reflection and refraction of light by different substances:

Answer 5

• angles of incidence and reflection are the same for the different materials
• as the angles of incidence and reflection do not depend on the material
• angle of refraction is different for the different materials as angle of refraction changes depending on the material

Question 6

Why would using a wider ray give less accurate results than using a narrow ray?

Answer 6

it would be harder to judge where the centre of the wider ray was causing a lerger uncertainty

Question 7

What type of error may have caused each angle of reflection to have a range of values?

Answer 7

random error