Unpolarized light of intensity 7.5 mW/m2 is sent into a polarizing sheet. What are (a) the...

Question:

Unpolarized light of intensity 7.5 mW/m{eq}^2 {/eq} is sent into a polarizing sheet. What are (a) the amplitude of the electric field component of the transmitted light and (b) the radiation pressure on the sheet due to it absorbing some of the light?

Electric Fields in EM waves:

Intensity is defined as the power over area for any quantity. This is no different for the case of electromagnetic waves. In addition to this definition, the intensity of the electromagnetic wave can be expressed in terms of its component electric field. The maximum electric field can be related to the intensity of the EM wave as:

{eq}\displaystyle I = c\epsilon_0 E^2 {/eq}

where:

• {eq}\displaystyle c = 3\ \times\ 10^8\ m/s {/eq} is the speed of light
• {eq}\displaystyle \epsilon_0 = 8.85\ \times\ 10^{-12}\ F/m {/eq} is the permittivity in free space constant
• E is the max electric field amplitude

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Given:

• {eq}\displaystyle I_0 = 7.5\ mW/m^2 = 0.0075\ W/m^2 {/eq} is the intensity of the unpolarized light

When unpolarized light goes through a... Electromagnetic Waves: Definition, Sources & Properties

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Chapter 20 / Lesson 6
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Electromagnetic waves are both electric and magnetic, and can travel without a medium. Learn about the definition, sources, and properties of electromagnetic waves.