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905-I: Photon Formulas 2

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905-I: Photon Formulas 2

BACK to Ladder The Electromagnetic Spectrum: Quantitative

In a previous pod, you learned the formulas that relate the frequency, energy, and wavelength of a photon of light. In this pod, you will continue using those formulas. Two changes make this pod more difficult. Firstly, not all photons presented are visible light, so you have a much wider range of order of magnitudes to consider for each variable. Secondly, each individual step is not listed. You need to know, on your own, when to complete the requisite conversions, when to use which formula, and when to refer to each constant.

Reference Information

Table of Electromagnetic Waves

Type of Wave
Wavelength
Radio Wave
greater than 1 meter
Microwave
between 1 millimeter and 1 meter
Infrared Light
between 700 nanometers and 1 millimeter

Visible Light

Red
between 635 nanometers and 700 nanometers
Orange
between 590 nanometers and 635 nanometers
Yellow
between 560 nanometers and 590 nanometers
Green
between 520 nanometers and 560 nanometers
Blue
between 450 nanometers and 520 nanometers
Violet
between 400 nanometers and 450 nanometers
Ultraviolet Light
between 10 nanometers and 400 nanometers
X-ray
between 1 picometer and 10 nanometers
Gamma Ray
less than 1 picometer

Formulas

$$ c = \lambda f $$

Symbol
Quantity
SI Unit
\( c \)
Speed of Light (3e8)
m/s
\( \lambda \)
wavelength
meters
\( f \)
frequency
Hertz (1/s)

Note that frequency is also sometimes denoted by the Greek letter nu: \( \nu \).

$$ E = h f $$

Symbol
Quantity
SI Unit
\( E \)
Energy of Photon
Joules (J)
\( h \)
Planck's Constant (6.626e-34)
Joule-seconds
\( f \)
frequency
Hertz (1/s)

Constants

SI units

Conversion Factors:

Problems

Each row contains one piece of information. From this one piece, determine the missing information. Record each item in the unit provided. Write all work, including formulas and conversion factors.

    Problem
    Type of Wave
    Wavelength
    Frequency
    Photon Energy
    Speed
  1. 630.
    nanometers
    teraHertz
    electron-volts
    m/s
  2. centimeters
    500.
    megahertz
    micro-electron-volts
    m/s
  3. millimeters
    80.0
    gigaHertz
    micro-electron-volts
    m/s
  4. 15.0
    nanometers
    petaHertz
    electron-volts
    m/s
  5. picometers
    petaHertz
    200.
    kilo-electron-volts
    m/s
  6. 420. nano
    meters
    teraHertz
    electron-volts
    m/s
  7. micrometers
    teraHertz
    124
    milli-electron-volts
    m/s
  8. Pick any FM radio station
    meters
    Between 87.5 and 108.0 megaHertz
    nano-electron-volts
    m/s
  9. Pick any AM Radio station
    meters
    between 550 and 1720 kHz
    nano-electron-volts
    m/s
  10. Highest energy gamma ray burst ever recorded
    meters
    Hertz
    1 tera-electron-volt
    m/s

BACK to Ladder The Electromagnetic Spectrum: Quantitative

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