Optics: Lenses and Mirrors

Lenses and Mirrors

• Light reflects off a surface
• Laws of reflection: Angle of incidence equals angle of reflection; incident ray, reflected ray, and normal lie in the same plane.
• Light bends when passing between different mediums (e.g., air to glass)
• Refraction: speed of light changes in different media
• Plane mirrors form virtual, upright, and same-sized images
• Spherical mirrors: Concave mirrors form real or virtual images depending on object position; used in telescopes and headlights. Convex mirrors form virtual, upright, and diminished images; used as security or rear-view mirrors.
• Mirror formula and magnification (details on page 190-191)
• Magnification: M>1 = enlarged image; M<1 = diminished image
• Convex lenses focus light to a point; used in magnifying glasses and cameras
• Concave lenses spread light outward; used in peepholes and corrective lenses for myopia
• Lens formula and magnification (details on page 204-205)
• Key terms: Focal point (F), Principal Axis, and Center of Curvature (C)

Electromagnetic Spectrum

• The electromagnetic spectrum is the range of all types of electromagnetic radiation.
• Electromagnetic waves are oscillating electric and magnetic fields that travel at the speed of light (c = 3 x 10⁸ m/s) in a vacuum.
• Properties of electromagnetic waves: transverse waves; can travel through a vacuum; all waves in the spectrum travel at the speed of light in a vacuum; wavelength and frequency are inversely related (c = λf).
• Radio waves
  • Uses: Communication (radio, TV), radar
  • Examples: FM and AM radio frequencies
• Microwaves
  • Uses: Microwave ovens, GPS, satellite communication
• Infrared (IR) radiation
  • Uses: Remote controls, thermal imaging, night vision
• Visible light
  • Range of colors: Red (longest wavelength, least energy) to Violet (shortest wavelength, most energy)
  • Uses: Vision, optical devices like cameras
• Ultraviolet (UV) light
  • Uses: Sterilization, detecting counterfeit money
  • Risks: Can cause skin cancer and eye damage
• X-rays
  • Uses: Medical imaging, security scanners
  • Risks: Prolonged exposure can damage tissues
• Gamma rays
  • Uses: Cancer treatment (radiotherapy), sterilizing medical equipment
  • Risks: Highly penetrative and harmful to living cells

Wave Properties and Relationships

• Wavelength (λ): Distance between two peaks of a wave
• Frequency (f): Number of wave cycles per second (measured in Hz)
• Energy (E) of a photon: E = hf (h = Planck's constant, 6.63 x 10⁻³⁴ J⋅s)
• Trends in the spectrum: As wavelength decreases, frequency and energy increase.

Explore the principles of optics including reflection and refraction, and the behavior of different types of lenses and mirrors. This quiz covers key concepts such as the laws of reflection, the mirror formula, and the formation of images. Perfect for students learning about light in physics!