Practice Page

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

Formulas

$$ c = \lambda f $$

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

$$ E = h f $$

Constants

• \( c = 3.00 \text{E}8 \) The speed of light is always 300,000,000 m/s.
• \( h = 6.626 \text{E} -34 \text{ J} \cdot \text{s} \)

SI units

• Wavelength
  • The SI unit for wavelength is meters.
  • You must convert wavelength to meters before using any formula.
  • When solving any formula for wavelength, the you solution will be in meters.
• Frequency
  • The SI unit for wavelength is Hertz.
  • You must convert frequency to Hertz before using any formula.
  • When solving any formula for frequency, the you solution will be in Hertz.
• Energy
  • The SI unit for wavelength is Joules.
  • You must convert energy to Joules before using any formula.
  • When solving any formula for energy, the you solution will be in Joules.

Conversion Factors:

• 1 Joule = 6.242E18 electron-volts (eV)
• Link to metric prefix reference

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
630.
nanometers
teraHertz
electron-volts
m/s
centimeters
500.
megahertz
micro-electron-volts
m/s
millimeters
80.0
gigaHertz
micro-electron-volts
m/s
15.0
nanometers
petaHertz
electron-volts
m/s
picometers
petaHertz
200.
kilo-electron-volts
m/s
420. nano
meters
teraHertz
electron-volts
m/s
micrometers
teraHertz
124
milli-electron-volts
m/s
Pick any FM radio station
meters
Between 87.5 and 108.0 megaHertz
nano-electron-volts
m/s
Pick any AM Radio station
meters
between 550 and 1720 kHz
nano-electron-volts
m/s
Highest energy gamma ray burst ever recorded
meters
Hertz
1 tera-electron-volt
m/s