Understanding Light: Wavelength and Electromagnetic Spectrum
32 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the formula to calculate wavelength of light?

  • C ÷ v
  • C × v
  • v = l/C
  • l = C/v (correct)

    • What is the speed of light in vacuum?

  • 2 × 10^8 m/s
  • 4 × 10^8 m/s
  • 5 × 10^8 m/s
  • 3 × 10^8 m/s (correct)

    • What is the range of wavelength for the visible spectrum of light?

  • 200 - 400 nm
  • 300 - 600 nm
  • 400 - 800 nm
  • 380 nm to about 780 nm (correct)

    • Which of the following regions of the electromagnetic spectrum has a wavelength range of 200 - 400 nm?

    <p>Near UV</p> Signup and view all the answers

    What is the relationship between the energy of light and its frequency?

    <p>Energy of light increases as frequency increases</p> Signup and view all the answers

    What is the order of colors in the visible spectrum, in order of increasing wavelength?

    <p>Violet, Blue, Cyan, Green, Yellow, Orange, Red</p> Signup and view all the answers

    Which type of spectroscopy is used to study the effects of high-energy electromagnetic radiation on atoms and molecules?

    <p>g-Ray spectroscopy</p> Signup and view all the answers

    Which of the following wavelengths of light is associated with the color red?

    <p>595-650 nm</p> Signup and view all the answers

    What is the complementary color of blue light with a wavelength of 435-480 nm?

    <p>Yellow-green</p> Signup and view all the answers

    Which range of wavelengths is considered the UV region?

    <p>200-400 nm</p> Signup and view all the answers

    What is the apparent color of the light with a wavelength of 560-580 nm?

    <p>Yellow-green</p> Signup and view all the answers

    Which type of electromagnetic radiation is associated with the longest wavelengths?

    <p>Red light</p> Signup and view all the answers

    What is the primary basis of spectrophotometric techniques?

    <p>Interaction of electromagnetic radiation with matter</p> Signup and view all the answers

    What is the dual nature of electromagnetic radiation?

    <p>It can be described as both waves and particles</p> Signup and view all the answers

    What is the application of spectrophotometry?

    <p>Both qualitative and quantitative determination of substances</p> Signup and view all the answers

    What is an advantage of spectrophotometry?

    <p>High selectivity</p> Signup and view all the answers

    Which of the following is NOT a type of chromatography?

    <p>Electrophoresis</p> Signup and view all the answers

    What is the instrumental method that is based on the separation of compounds?

    <p>Chromatography</p> Signup and view all the answers

    What type of transitions can be induced by energy that is not sufficient to cause electronic transitions?

    <p>Vibrational and rotational transitions</p> Signup and view all the answers

    What is the ratio of energy of electronic transitions to vibrational transitions?

    <p>10,000:1</p> Signup and view all the answers

    What occurs when a molecule absorbs photons in the UV-VIS region?

    <p>Electronic transition</p> Signup and view all the answers

    What is the energy level of the ground state?

    <p>Lowest energy level</p> Signup and view all the answers

    What type of electronic transition involves the excitation of an electron from a non-bonding orbital?

    <p>n → s*</p> Signup and view all the answers

    What is the wavelength of light associated with the s → s* electronic transition?

    <p>150 nm</p> Signup and view all the answers

    What type of electronic transition involves the excitation of an electron from a π bonding orbital?

    <p>π → π*</p> Signup and view all the answers

    What is the equation that represents the total energy of a molecule?

    <p>E total = E electronic + E vibrational + E rotational</p> Signup and view all the answers

    What is the term for a substituent that causes a shift to a longer wavelength with an increase in absorption intensity when attached to a chromophore?

    <p>Auxochromes</p> Signup and view all the answers

    What is the term for the shift of lmax to a shorter wavelength due to substitution or solvent effects?

    <p>Hypsochromic shift</p> Signup and view all the answers

    What is the term for an increase in absorption intensity?

    <p>Hyperchromic effect</p> Signup and view all the answers

    What is the term for the shift of lmax to a longer wavelength due to substitution or solvent effects?

    <p>Bathochromic shift</p> Signup and view all the answers

    What is the term for a decrease in absorption intensity?

    <p>Hypochromic effect</p> Signup and view all the answers

    What are the substituents that do not absorb ultraviolet radiations but cause a shift to a longer wavelength with an increase in absorption intensity when attached to a chromophore, called?

    <p>Auxochromes</p> Signup and view all the answers

    Study Notes

    Pharmaceutical Instrumental Analysis

    • Chromatographic methods: HPLC, GC, PC, TLC, IC
    • Miscellaneous methods: Electrophoresis (CE), Elemental analysis, Thermal analysis
    • Spectrophotometry: measures interaction of electromagnetic radiation with matter at specific energy levels
    • Advantages of spectrophotometry: ease and convenience, wide applications, high selectivity, high sensitivity

    Electromagnetic Radiation (EMR)

    • Described as both waves and particles (photons)
    • Consists of regular electric and magnetic fluctuations
    • Energy (E) of light increases as frequency (n) increases or wavelength (l) decreases
    • Speed of light (C) in vacuum: 3 x 10^8 m/s

    Electromagnetic Spectrum

    • Types of light: increasing frequency (n)
    • UV region: 10-200 nm (far UV), 200-400 nm (near UV)
    • Visible region: 380-780 nm
    • Visible spectrum consists of 7 colors: violet, blue, cyan, green, yellow, orange, red

    UV-Visible Region

    • Wavelength (nm) and corresponding colors:
      • 200-400: UV
      • 400-435: Violet (yellow-green)
      • 435-480: Blue (yellow)
      • 480-490: Blue-green (orange)
      • 490-500: Green-blue (red)
      • 500-560: Green (purple)
      • 560-580: Yellow-green (violet)
      • 580-595: Yellow (blue)
      • 595-650: Orange (green-blue)
      • 650-780: Red (blue-green)

    Spectroscopic Methods

    • Types of spectroscopy based on frequency of EMR
    • Examples: γ-Rays, X-Rays, UV-Visible radiation

    Electronic Transitions

    • Absorption of energy results in electronic transitions
    • Types of electronic transitions:
      1. s → s* (e.g. alkanes, λ ~ 150 nm)
      2. n → s* (e.g. R-NH2, R-OH, R-SH, λ ~ 190 nm)
      3. p → p* (e.g. alkenes, alkynes, carbonyl, λ < "s" electrons)
      4. n → p* (e.g. auxochromes)

    Important Terms

    • Hyperchromic effect: increase in absorption intensity
    • Hypochromic effect: decrease in absorption intensity
    • Bathochromic shift (red shift): shift to longer wavelength (lower energy)
    • Hypsochromic shift (blue shift): shift to shorter wavelength (higher energy)

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz covers the basics of light, including its wavelength, speed, and frequency, as well as the electromagnetic spectrum. Test your understanding of these fundamental concepts in physics.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser