| Convex lense structure, where's the Principal of Focus & Focal length & how does the image appear? | - thicker in the middle than it is at the edges.
- Parallel light rays that enter the lens converge & come together at a point called the principal focus
- The distance from the lens to the principal focus is called the focal length
IMAGE IS: Inverted, diminished or magnified, real |
| Concave lense structure, where's the principal of focus & how does the image appear? | - thinner in the middle than it is at the edges
- This causes parallel rays to diverge & separate but appear to come from a principle focus on the other side of the lens
IMAGE IS: Upright, diminished or magnified, virtual |
| Real & Virtual images & How to draw a ray diagram | Virtual image - appears to come from behind the lens
Real image - an image that can be projected onto a screen
HOW TO DRAW A RAY DIAGRAM:
1) Draw a ray from the object to the lens that is parallel to the principal axis. Once through the lens, the ray should pass through the principal focus.
2) Draw a ray which passes from the object through the centre of the lens |
| Absorption, reflection and transmission of visible light | Visible light in order of increasing frequency & decreasing wavelengths: red - orange - yellow - green - blue - indigo - violet
ABSORPTION OF LIGHT:
- Happens at the boundary between two different materials
- the energy of the wave is transferred to the particles in the surface(internal energy of the particles increase)
- some wavelengths or colours of light are absorbed, others are reflected = the colour our eyes detect
TRANSMISSION OF LIGHT:
- When light passes through translucent/transparent objects
- Eg, an orange filter transmits orange light but absorbs all the other colours |
