Atomic Spectrum Notes/Practice Problems
Part A: Concepts
1. Electromagnetic Spectrum – A range containing all the possible frequencies and
wavelengths of electromagnetic radiation
2. The Sun is the main source of the electromagnetic energy we use.
3. Electromagnetic radiation is a type of energy that travels in waves.
4. Electromagnetic waves can be described in terms of its wavelength and frequency.
● All electromagnetic waves travel through space at the same velocity known as the
speed of light
o c = 3.00 x 108 m/s
● All electromagnetic waves have the same basic form, as shown in the diagram below.
The distance between two consecutive peaks of a wave is its
wavelength. Every wave has a characteristic wavelength.
● Wavelength is an identifying property of a wave
o The Greek symbol λ (lambda) is used to denote wavelength
o Wavelength is measured in meters (m)
● Frequency is an identifying property of a wave
o Determined by the number of peaks that pass through a fixed point every
second
o Frequency is expressed in s-1 or Hz
o
Every wave has a characteristic frequency.
High-frequency waves have more energy
than low-frequency waves.
5. Wavelength and
related.
Frequency are inversely
● As wavelength increases, frequency decreases and/or as frequency increases,
wavelength decreases
● Relationship between wavelength and frequency represented by this equation:
o c=λxf
▪ λ = wavelength (m)
▪ f = frequency (s-1 or Hz)
▪ c = 3.00 x 108 m/s (Speed of Light; constant)
6. Max Planck proposed that electromagnetic radiation was emitted in photons, which are
small packets of energy.
● Planck’s constant is equal to 6.626 x 10-34 Js
7. Energy and Frequency are directly related.
● As frequency increases, energy increases
● Represented by the equation:
o E = hf
▪ E = energy (J)
▪ h = 6.626 x 10-34 Js (Planck’s constant)
▪ f = frequency (s-1 or Hz)
8. Mathematical Equations for Energy, Frequency, and Wavelength
● c=λxf
o Solved for wavelength:
▪ λ=c/f
o Solved for frequency:
▪ f=c/λ
● E = hf
o Using wavelength to solve for energy
▪ E = (h x c) / λ
9. Electromagnetic Spectrum: Wavelength, Frequency, Energy
Part B: Calculations
1. The relationship between wavelength and frequency is c = λ x f. Calculate the wavelength of
an electromagnetic wave that has a frequency of 5.2 x 1012 Hz. The speed of light is 3.0x108 m/s.
2. The relationship between wavelength and frequency is c = λ x f. If the wavelength of an
electromagnetic wave is 4.8 x 10-12 m, calculate the frequency in Hz. The Speed of Light is 3.0 x
108 m/s.
3. The relationship between energy and frequency is E = h x f. A microwave can have a
frequency of 3.8 X 1010 Hz. How much energy does this microwave give off in joules? Planck's
Constant is 6.626 x 10-34 Js.
4. The relationship between wavelength and energy is E = (h x c) / λ. A typical cell phone uses
wavelengths of 0.36 meters. How much energy does this wave have?
Planck's Constant is 6.626 x 10-34 Js. The speed of light is 3.00 x 108 m/s.
5. The relationship between frequency and energy is E = h x f. A particular nuclear process
releases a single gamma ray photon with an energy of 4.75x10-14 joules. What is the frequency
of this radiation? Planck's Constant is 6.626 x 10-34 Js.