Study Notes
Light is a form of energy that travels in waves and can move through empty space. It is responsible for phenomena such as shadows and reflection. Reflection — the bouncing back of light from a surface. Example: Light reflecting off a mirror. Refraction — the bending of light as it passes from one medium to another. Example: A straw appearing bent in a glass of water. Specular Reflection — reflection from a smooth surface in a single direction. Example: A clear image seen in a mirror. Diffuse Reflection — reflection from a rough surface causing scattering. Example: Light reflecting off a table surface. Virtual Image — an image formed by rays that appear to come from a certain point but do not actually converge there. Example: The image seen in a mirror.
Exam Tips
Key Definitions to Remember
- Reflection: The bouncing back of light from a surface.
- Refraction: The bending of light as it passes from one medium to another.
- Specular Reflection: Reflection from a smooth surface in a single direction.
- Diffuse Reflection: Reflection from a rough surface causing scattering.
Common Confusions
- Confusing reflection with refraction.
- Thinking that light needs a medium to travel through.
Typical Exam Questions
- What is the angle of reflection if the angle of incidence is 30°? The angle of reflection is also 30°.
- How does light behave when it moves from air into water? It slows down and bends towards the normal.
- What is a virtual image? An image formed by rays that appear to come from a certain point but do not actually converge there.
What Examiners Usually Test
- Understanding of the laws of reflection and refraction.
- Ability to draw and interpret ray diagrams.
- Differences between specular and diffuse reflection.