Answer:
Electromagnetic radiation is one of the many ways that energy travels through space. The heat from a burning fire, the light from the sun, the X-rays used by your doctor, as well as the energy used to cook food in a microwave are all forms of electromagnetic radiation. While these forms of energy might seem quite different from one another, they are related in that they all exhibit wavelike properties.
Keep in mind that some waves (including electromagnetic waves) also oscillate in space, and therefore they are oscillating at a given position as time passes. The quantity known as the wave’s frequency refers to the number of full wavelengths that pass by a given point in space every second; the SI unit for frequency is Hertz (\text{Hz})(Hz)left parenthesis, start text, H, z, end text, right parenthesis, which is equivalent to “per seconds” \Big((left parenthesiswritten as \dfrac{1}{\text{s}}
s
1
start fraction, 1, divided by, start text, s, end text, end fraction or \text{s}^{-1}\Big)s
−1
)start text, s, end text, start superscript, minus, 1, end superscript, right parenthesis. As you might imagine, wavelength and frequency are inversely proportional: that is, the shorter the wavelength, the higher the frequency, and vice versa. This relationship is given by the following equation:
c=\lambda \nuc=λν
Explanation:
A particular wave of electromagnetic radiation has a frequency of 1.5\times10^{14}\text{ Hz}1.5×10
14
Hz1, point, 5, times, 10, start superscript, 14, end superscript, start text, space, H, z, end text.
What is the wavelength of this wave?
We can start with our equation that relates frequency, wavelength, and the speed of light.
c=\lambda \nuc=λνc, equals, lambda, \nu
Next, we rearrange the equation to solve for wavelength.
\lambda=\dfrac{c}{\nu}λ=
ν
c
lambda, equals, start fraction, c, divided by, \nu, end fraction
Lastly, we plug in our given values and solve.
\lambda=\dfrac{3.00\times10^8\dfrac{\text{m}}{\cancel{\text{s}}}}{1.5\times10^{14}\dfrac{1}{\cancel{\text{ s}}}}=2.00\times10^{-6}\text{ m}λ=
1.5×10
14
s
1
3.00×10
8
s
m
=2.00×10
−6
mlambda, equals, start fraction, 3, point, 00, times, 10, start superscript, 8, end superscript, start fraction, start text, m, end text, divided by, start cancel, start text, s, end text, end cancel, end fraction, divided by, 1, point, 5, times, 10, start superscript, 14, end superscript, start fraction, 1, divided by, start cancel, start text, space, s, end text, end cancel, end fraction, end fraction, equals, 2, point, 00, times, 10, start superscript, minus, 6, end superscript, start text, space, m, end text
Concept check: What would you expect to happen to the frequency of a light wave if its wavelength were increased by a factor of 101010?
[Show the answer]
1010\dfrac{1}{10}
start fraction, 1, divided by, 10, end fraction
Period
The last quantity we will consider is the period of a wave. A wave’s period is the length of time it takes for one wavelength to pass by a given point in space. Mathematically, the period (TTT) is simply the reciprocal of the wave’s frequency (fff):
T=\dfrac{1}{f}T=
f
1
T, equals, start fraction, 1, divided by, f, end fraction
The units of period are seconds (\text{s}sstart text, s, end text).
Now that we have an understanding of some basic properties of waves, we’ll look at the different types of electromagnetic radiation.
