Lenses

• Convex ray diagram:

  
• Concave lens:

  
• Concave ray diagram:

  
• Convex lens:

  
• What is a real image?

  A real image is formed when light rays converge and can be projected onto a screen.
• What is a virtual image?

  A virtual image is where light rays appear to converge or diverge from a point, but the image cannot be projected onto a screen.
• What does the colour of an opaque object depend on?

  The wavelengths of light most storngly reflected
• What is white colour?

  Combination of all colours
• Black objects...

  reflect all wavelengths equally
• White objects...

  Reflect all wavelengths equally
• Transparent and translucent objects...

  TRANSMIT light
• What do colour filters do?

  Absorb/transmit certain colors.