Lens

• What is the axis of a lens?

  A line through the lens's center and curved surfaces
• What is the principal focus of a converging lens?

  Where parallel rays converge after hitting the lens
• How is the principal focus of a diverging lens defined?

  where rays hitting lens parallel to the axis is coming from
• What is the focal length of a lens?

  The distance from the lens center to the principal focus
• What happens to light rays when they enter a lens?

  They bend towards the normal
• What happens to light rays when they leave a lens?

  They bend away from the normal
• What are the characteristics of converging and diverging lenses?

  • Converging Lens:
  • Bulges outwards
  • Brings parallel rays together
  • Also called convex lens

  
  

  • Diverging Lens:
  • Caves inwards
  • Spreads parallel rays apart
  • Also called concave lens