Electromagnetic Radiation Principles And Blackbody Radiation

Homework Content

Equations and Assumptions

Relationship between Wavelength and Frequency

$$\begin{split}c &= f{\lambda} \\ c &= \textrm {speed of light} = 3.0 * 10^8 \textrm {meters per second} \\ f &= \textrm {frequency} \\ {\lambda} &= \textrm {wavelength}\end{split}$$

Stefan-Boltzman law

$$\begin{split}M_{\lambda} &= {\sigma}T^4 \\ M_{\lambda} &= \textrm {Total emitted radation in Watts per square meter} \\ {\sigma} &= \textrm {Stefan-Boltzmann constant} = 5.6697 * 10^{-8} Wm^{-2}K^{-4} \\ T &= \textrm {Temperature in Kelvin}\end{split}$$

Wien’s diplacement law

$$\begin{split}{\lambda}_\textrm{max} &= \frac{k}{T} \\ {\lambda}_\textrm{max} &= \textrm {Maximum emitted wavelength} \\ k &= 2898 {\mu}m K \\ T &= \textrm {Temperature in Kelvin} \\\end{split}$$

Problems

Show all your work clearly with all units and in detail, leading up to the answer:

1. If the wavelength of an EM wave is 0.7 micrometers.

1. How many nanometers is this and what is the color of this wave?
2. What is the frequency of this wave?

2. An electromagnetic wave has a frequency of 2.0 x 10⁷ Hertz.

1. What is its wavelength?
2. To which part of the electromagnetic spectrum does this wave belong?

3. The maximum wavelength emitted by a cooling blackbody is 200 nanometers. What is the temperature of the blackbody in:

1. Kelvin
2. degrees Celsius
3. degrees Fahrenheit

4. If the temperature of a blackbody is 75 degrees Fahrenheit, what is the wavelength of the maximum radiation emitted by the object?

1. measured in nanometers
2. measured in micrometers

5. Why is it that you should or should not put a sensor to look at reflected radiation from the Earth at 0.2 micrometers? Please elaborate on the specific reasons.
6. Which molecules in the atmosphere are responsible for the maximum absorption of incoming sunlight?

Metadata

Title:Electromagnetic Radiation Principles And Blackbody Radiation

CreationDate:06/20/2013

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