{"id":1781,"date":"2016-08-23T20:43:44","date_gmt":"2016-08-24T00:43:44","guid":{"rendered":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/?page_id=1781"},"modified":"2017-04-27T11:24:32","modified_gmt":"2017-04-27T15:24:32","slug":"lab-3-background","status":"publish","type":"page","link":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/lab-3-polarization-of-light\/lab-3-background\/","title":{"rendered":"Background"},"content":{"rendered":"

Suppose that we want to specify the orientation of a plane electromagnetic wave in space (this could be helpful for understanding radio reception, to pick a random example).\u00a0 Plane electromagnetic waves are transverse waves, so we know that the electric and magnetic field vectors are oscillating perpendicularly to the direction of travel, as shown in Fig. 1<\/a>.<\/p>\n

\"EMWave2\"

Figure 1: An electromagnetic wave<\/p><\/div>\n

We also know that the electric and magnetic field vectors are perpendicular to each other, but that still leaves an infinite number of options for orienting the wave.\u00a0 Here are just two more possibilities:<\/p>\n

\"EMWave1\"

Figure 2: Another electromagnetic wave<\/p><\/div>\n

\"EMWave3\"

Figure 3: Yet another electromagnetic wave<\/p><\/div>\n

To eliminate this remaining freedom we can specify the behavior of the electric field vector. If the electric field vector stays in a fixed plane as the wave travels (forcing the magnetic field vector to stay in a perpendicular fixed plane) we say that the wave is linearly (or plane) polarized in the direction of the electric field vector.\u00a0 So, the wave in Fig. 1<\/a> is linearly polarized in the \\(\\hat{y}\\) direction, the wave in Fig. 2<\/a> is linearly polarized in the \\(\\hat{z}\\) direction, and the wave in Fig. 3<\/a> is linearly polarized in a direction \\(45^{\\circ}\\) between the two,\u00a0\\(\\frac{1}{\\sqrt{2}}\\left(\\hat{y}+\\hat{z}\\right)\\).<\/p>\n

If we add up many waves with random polarizations, so no particular direction of the electric field vector is favored, we have unpolarized light. We will explore how unpolarized light can become polarized, and we will attempt to verify the <\/a>law of Malus which governs the intensity of light transmitted through consecutive ideal polarizers<\/a> with polarizing directions differing by an angle \\(\\theta\\):<\/p>\n

$$I_{\\rm transmitted}=I_{\\rm incident}\\cos^{2}\\theta.$$<\/p>\n

Equipment<\/a> Data Collection and Analysis<\/a> Summary Questions<\/a><\/p>\n

\"badge\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Suppose that we want to specify the orientation of a plane electromagnetic wave in space (this could be helpful for understanding radio reception, to pick a random example).\u00a0 Plane electromagnetic waves are transverse waves, so we know that the electric and magnetic field vectors are oscillating perpendicularly to the direction of travel, as shown in […]<\/p>\n","protected":false},"author":289,"featured_media":0,"parent":1779,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1781","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/pages\/1781","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/users\/289"}],"replies":[{"embeddable":true,"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/comments?post=1781"}],"version-history":[{"count":0,"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/pages\/1781\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/pages\/1779"}],"wp:attachment":[{"href":"https:\/\/courses.bowdoin.edu\/physics-1140-lab-manual\/wp-json\/wp\/v2\/media?parent=1781"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}