Required Practical - Reflection and Refraction
Physics: AQA GCSE Higher, topic 6.2.7
Reflection and Refraction of Light
This study explores how the angle of reflection compares with the angle of incidence when light hits different surfaces, and how light refracts when passing through different materials.
Apparatus
- Ray box with a slit and a focusing lens
- Ruler
- A3 paper
- Protractor
- Rectangular acrylic block
- Rectangular glass block
- Pencil or fine pen
Method
- Get a ray box with a single slit and a lens to make a thin beam of light.
- Place an A3 sheet on the table and draw a straight line near the centre.
- Use a protractor to draw a second line perpendicular to that line in the middle — label it as the normal (N).
- Place the acrylic block on the first line, with the 'N' line in the middle of one side. Trace around the block to mark its position.
- Point the ray box at where the 'N' line meets the block. This light is called the incident ray.
Method (continuation)
- Adjust the ray box until you see the light ray bouncing off (reflected) and another ray coming out the other side (transmitted).
- Mark the light paths:
- Incoming (incident) ray with one 'X'.
- Reflected ray with another 'X'.
- Outgoing (transmitted) ray with two 'X's (inside and exiting the block).
- Remove the block and connect the 'X's to draw the light paths.
- Replace the acrylic block with a rectangular glass block and repeat the steps for comparison.
Analysis
- Measure the angle of incidence (i), angle of reflection (r), and angle of refraction for both materials.
- Law of Reflection:
- Compare the angle of incidence and the angle of reflection for each surface.
- They should be equal if the law is true.
- Refraction:
- Compare the angle of incidence with the angle of refraction for each material.
- The glass should bend light more than the acrylic block due to its higher refractive index.
Safety Precautions
- Hot ray box bulb may cause minor burns.
- Avoid touching the bulb; allow time to cool after use.
- Sharp edges on glass block may cause small cuts.
- Handle the blocks carefully and gently.
Test yourself on Required Practical - Reflection and Refraction
What happens to light when it travels from air into a denser material such as glass?
Which of the following best describes the law of reflection?
What is the purpose of using a ray box in this experiment?