Science: Electromagnetic Radiation - Wavelength, Frequency, and Photon Energy

By E Saylor

Useful Information: Note that both c and h are constants.

c = speed of light = 3 x 10¹⁰ cm/sec = 3 x 10⁸ m/sec

h = Planck's constant = 6.626 x 10^-34 J/sec

Useful Formulas

c = wavelength x frequency

energy of a photon = h x frequency

Useful Units and Conversions

nano means "billionth": 1 nm = 1 x 10^-9 m OR 1 x 10⁹ nm = 1 m

mega means "million": 1 x 10⁶ Hz = 1 MHz

Frequency refers to the number of waves that pass by each second and is measured in a unit called Hertz (Hz).

Directions: Find the requested information in each question by using the formulas provided above.

frequency: ?

energy of a photon: ?

wavelength: ?

energy of a photon: ?

frequency: ?

energy of a photon: ?

wavelength: ?

energy of a photon: ?

frequency: ?

energy of a photon: ?

Wavelength: ?

Energy of a photon: ?

frequency: ?

energy of a photon: ?

wavelength: ?

energy of a photon: ?

frequency: ?

energy of a photon: ?

frequency: ?

energy of a photon: ?

Electromagnetic radiation propagates through space as waves. All graphs represent the number of waves propagating through the same distance in a one-second interval. Remember that all forms of electromagnetic radiation travel at the speed of light through a vacuum.

Which of the following waves would have the lowest energy photons? In answering this question, be sure to compare all three waves in terms of their relative wavelength, frequency, as well as energy.