محاضرة 6

• What is the electromagnetic spectrum (EMS)?

  Range of frequencies of electromagnetic radiation
• Which types of radiation are included in the electromagnetic spectrum?

  UV, visible, IR, gamma rays, X-rays, radio waves

  
• What phenomenon occurs when light spreads out through a narrow slit?

  Diffraction
• Which color of light is refracted when sunlight passes through glass?

  Red
• Which type of electromagnetic radiation has the longest wavelength?

  Radio waves
• What causes the blue color of the clear sky?

  Scattering by atmospheric particles
• How many colors does white light consist of?

  Seven
• What is light classified as within the electromagnetic spectrum?

  Electromagnetic radiation (EMR)
• What are the dual properties of light?

  Electrical and magnetic properties
• In what mediums can light travel?

  Air and vacuum
• Where does light travel fastest?

  In vacuum
• What does a prism do to white light?

  Separates it into original colors
• What is the wavelength range of visible light?

  400–700 nanometers (nm)
• What is reflection of light?

  Light rays are sent back from a surface
• What is refraction of light?

  Bending of light when entering a different medium
• What does Snell's Law describe?

  Relationship between angles of incidence and refraction

  
• What is the refractive index (n) of air?

  1
• What happens to light when it travels from air to glass?

  It bends toward the normal plane
• Which substance has the highest refractive index?

  Diamond
• How is the refractive index defined?

  Ratio of speed of light in vacuum to material
• What is absorption of light?

  When matter captures electromagnetic radiation
• What are the four measurable properties of wave motion?

  Wavelength, frequency, amplitude, wavenumber
• What is wavelength (λ)?

  Distance between two successive crests or troughs
• What is frequency (υ)?

  Number of waves per second
• What is wavenumber (ύ)?

  Number of waves in cm
• Calculate the wavenumber of light with λ=300 nm.

  $33333 \text{ cm}^{-1}$
• What is amplitude?

  Maximum value reached in wave motion
• What is the velocity of light (C) formula?

  $C =$$\lambda \times \nu$
• What is the formula for energy of photons (E)?

  $E =$$h\nu =$$hC/\lambda$
• How does energy of light relate to wavelength?

  Energy is inversely proportional to wavelength
• Which type of radiation has the highest energy?

  Gamma rays
• Which type of radiation has the lowest energy?

  Radio waves
• What is spectroscopy?

  Study of EMS interaction with matter
• What are electronic transitions?

  Movement of electrons between energy levels

  
• What is Planck’s constant (h)?

  Approximately 6.626 \times 10^{-34} \text{ J·s}
• How is photon energy (E) calculated?

  $E =$$h\nu \text{ or } E =$$hC/\lambda$
• What is transmission of light?

  Passage of light through a medium
• What does the dual nature of light refer to?

  Wave-like and particle-like behavior
• What is the speed of light (C) in a vacuum?

  Approximately $3 \times 10^8 \text{ m/s}$
• What is ultraviolet (UV) light?

  Radiation with wavelengths shorter than visible light