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Lenses & Visible Light - Coggle Diagram
Lenses & Visible Light
Visible Light
Electromagnetic wave
Transverse wave
Travels at 3 × 10⁸ m/s in a vacuum
Colours of Visible Light
Red
Orange
Yellow
Green
Blue
Indigo
Violet
Red Light
Longest wavelength
Lowest frequency
Violet Light
Shortest wavelength
Highest frequency
Refraction
Change in direction of light
Caused by change in speed
Occurs when entering different medium
Less Dense → More Dense
Bends towards normal
More Dense → Less Dense
Bends away from normal
Lenses
Convex Lens
Converging lens
Thicker in middle
Brings light rays together
Concave Lens
Diverging lens
Thinner in middle
Spreads light rays apart
Focal Point
Point where rays meet
Represented by F
Focal Length
Distance from lens to focal point
Ray Diagrams
Through Centre
Continues straight
Parallel Ray
Passes through focal point
Convex Lens Images
Object beyond focal length
Real image
Inverted
Object within focal length
Virtual image
Upright
Magnified
Magnification
Makes image appear larger
Equation
Magnification = Image Height ÷ Object Height
Magnification and Lenses
Magnifying glass
Camera
Microscope
Telescope
Required Practical
Measure focal length
Use illuminated object
Use screen
Move screen until image sharp
Measure lens to image distance
Eye
Cornea refracts light
Lens focuses light
Image formed on retina
Ciliary Muscles
Change thickness of lens
Eye Defects
Long Sightedness
Difficult to focus on near objects
Corrected with convex lens
Short Sightedness
Difficult to focus on distant objects
Corrected with concave lens