Waves

• What do all waves transfer without transferring matter?

  Energy
• How are longitudinal waves characterized in terms of oscillation direction?

  The direction of oscillations is parallel to the direction of energy transfer.
• What do we call the regions where particles bunch up in longitudinal waves?

  Compressions
• What do we call the regions where particles are spread out in longitudinal waves?

  Rarefactions
• How are transverse waves characterized in terms of oscillation direction?

  The direction of oscillations is perpendicular to the direction of energy transfer.
• What is a waveform and what does it represent?

  • A graphical representation of a wave
  • Displacement is on the y-axis
  • Time or distance is on the x-axis
• What is the peak of a wave called?

  Amplitude
• What does the amplitude of a wave represent?

  The maximum displacement from equilibrium.
• What symbol is used to represent wavelength?

  Lambda (λ)
• How is the wavelength measured?

  It is measured in meters.
• What does the time period of a wave represent?

  The time it takes for one complete wave to pass.
• What is frequency in relation to waves?

  It is how many waves pass a point every second.
• What is the formula for frequency?


  Frequency (f) is equal to 1/Time Period (T)
• How can you find frequency from a waveform?

  Measure the time period and then calculate \( f = \frac{1}{T} \).
• What is the wave equation?

  The wave equation is \( V = f \cdot λ \), where V is wave speed, f is frequency, and λ is wavelength.
• What is the range of visible light wavelengths?

  From around 400 to 750 nanometers (4 to 7.5 × 10^-7 m).
• How does the intensity of a wave relate to its amplitude?

  The intensity is proportional to the amplitude squared.
• What happens to light waves when they move from one medium to another?

  They change speed and wavelength, and may change direction (refraction).
• What is refraction?

  Refraction is the change in direction of a wave as it passes from one medium to another at an angle.
• How does the angle of refraction compare to the angle of incidence when light slows down?

  The angle of refraction is smaller than the angle of incidence.
• What is the refractive index symbol?

  n
• How is the refractive index calculated?

  It is the ratio of the speed of light in a vacuum to the speed of light in the medium.
• What does Snell's law describe?

  It describes the relationship between the angles of incidence and refraction and the refractive indices of two media.
• What happens to blue light's refractive index compared to red light's in the same medium?

  Blue light's refractive index is higher than red light's.
• What is dispersion in the context of light?

  Dispersion is the separation of light into its component colors due to varying refractive indices.
• What is the critical angle?

  The critical angle is the angle of incidence that results in an angle of refraction of 90°.
• What happens when the angle of incidence exceeds the critical angle?

  No light is refracted out of the block; all light is reflected back inside.
• How is the critical angle calculated using Snell's law?


  By using the equation \( \sin \Theta_c = \frac{n_2}{n_1} \).
• How do optical fibers work?

  They use total internal reflection to transmit light through a glass core surrounded by a cladding with a lower refractive index.
• What is modal dispersion in optical fibers?

  It is the spreading of light as it travels down a fiber, causing different paths and times to reach the end.
• What are some methods to mitigate modal dispersion?

  Make the fiber thinner, use repeaters, or use graded index fibers.
• What is the function of lenses in optics?

  • Lenses use refraction to converge or diverge light rays.
  • Convex lenses converge light rays to a principal focus.
  • Concave lenses diverge light rays.
• What is the principal focus of a convex lens?

  It is the point where parallel rays of light converge after passing through the lens.
• What is the distance from the center of the lens to the principal focus called?

  Focal length
• How does a convex lens project an image?

  By using light rays from the top of the object and converging them at a point.
• What happens when the object is very close to a convex lens?


  The rays do not meet, resulting in a virtual image that is magnified and upright.
• What type of image do concave lenses always produce?

  A virtual image
• What is the power of a lens?

  The power is the reciprocal of the focal length, measured in diopters.
• What is the full lens equation?

  The full lens equation is \( \frac{1}{f} = \frac{1}{U} + \frac{1}{V} \).
• How does a polarizing filter affect light emitted from the Sun?

  It only lets half of the light through, transmitting waves of certain orientations.