How Lenses Work

• How do lenses focus light?

  By using refraction to bend light rays
• What are the two main types of lenses?

  Convex and concave lenses
• What shape do convex lenses have?

  Outwards bulge in the center
• What happens to parallel rays of light when they pass through a convex lens?

  They refract inwards to a single point
• What is another name for a convex lens?

  Converging lens
• How do concave lenses affect parallel rays of light?

  They refract them outwards, dispersing light
• How do we determine the direction of refracted rays in lenses?

  By tracing virtual lines from the principal focus
• What is the principal focus of a lens?

  The point where light rays converge or appear to diverge
• What is the distance between the principal focus and the center of the lens called?

  Focal length
• How does the curvature of a lens affect its power?

  More curvature increases the lens's power
• What is the difference between real and virtual images?

  Real images are formed by actual light convergence
• How is a real image formed?

  When light rays converge to form an image
• What happens to the image of an object when viewed through a lens?

  It is inverted and can be captured on a screen
• Why do we not notice the inversion of images in our eyes?

  Our brain corrects the inverted images
• How are virtual images formed?

  When light rays do not actually converge
• What are the characteristics of convex and concave lenses?

  • Convex lenses:
  • Bulge outwards
  • Converge light rays
  • Form real images
  • Concave lenses:
  • Cave inwards
  • Diverge light rays
  • Form virtual images
• What is the significance of the principal focus in lenses?

  • Point where light rays converge or appear to diverge
  • Exists on both sides of the lens
  • Determines the focal length
• What factors affect the power of a lens?

  • Curvature of the lens
  • Material of the lens
  • Focal length