Waves

• What do waves transfer from one point to another?

  Energy
• What does it mean for particles in waves to oscillate?

  They vibrate back and forth about a fixed point
• In a longitudinal wave, how do particles oscillate?

  Parallel to the direction of energy transfer
• In a transverse wave, how do particles oscillate?

  Perpendicular to the direction of energy transfer
• What are the two types of waves mentioned?

  • Longitudinal waves
  • Transverse waves
• What is the amplitude of a wave?

  Maximum size of the wave from the middle
• What is the wavelength symbol and its unit of measurement?

  Wavelength (λ) is measured in metres
• How is wavelength defined?

  Distance between two corresponding points on the wave
• What is frequency and how is it measured?

  How many waves pass by every second, measured in Hertz
• What are the key characteristics of waves discussed?

  • Waves transfer energy
  • Particles oscillate
  • Types: Longitudinal and Transverse
  • Amplitude: maximum size
  • Wavelength: distance between points
  • Frequency: waves per second
• What is the main topic of today's video?

  Focus and dispersion of light using lenses
• 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 is the principal focus of a convex lens?

  Point where parallel rays converge
• What is another name for a convex lens?

  Converging lens
• How do concave lenses refract light?

  They disperse light rays outwards
• How do we determine the direction of refracted rays in lenses?

  By tracing virtual lines from the principal focus
• What is the relationship between principal focus and lens symmetry?

  All lenses have a principal focus on both sides
• What is the focal length?

  Distance between principal focus and lens center
• How does the curvature of a lens affect its power?

  More curvature means a more powerful lens
• What materials can increase a lens's power?

  Materials that refract light more strongly
• What defines a real image?

  Formed when light rays actually converge
• How is a real image formed in the eye?

  Light rays converge on the retina
• Why don't we notice the inversion of real images?

  Our brain corrects the inverted images
• What is a virtual image?

  Formed when light rays don't converge
• How do virtual rays differ from real rays?

  Virtual rays are traced back, not real
• What should you mention when describing images in exams?

  Whether they are real or virtual
• How would you describe a real image in terms of orientation and size?

  Inverted and smaller than the object
• How would you describe a virtual image in terms of orientation and size?

  Upright and smaller than the object
• What are the key differences between real and virtual images?

  • Real images:
  • Formed by converging light rays
  • Can be captured on a screen
  • Typically inverted
  • Virtual images:
  • Formed by diverging light rays
  • Cannot be captured on a screen
  • Typically upright
• What factors affect the power of a lens?

  • Curvature of the lens:
  • More curvature = more power
  • Material of the lens:
  • Stronger refractive materials increase power