Oversea Studying

Physics 5 Major Practical 1 Kathryn PARKER, Line 5
Topic Chosen:
“Investigating polarization”
Focused research question:

“What effect does the angle between crossed polaroids have on the intensity of the light transmitted?”
Aim:

      To investigate the relationship between the intensity of light transmitted through crossed polaroids and the angle between them, thereby obtaining results that conform with or dispute Malus’ Law.

Introduction:

Polarization is a property of electromagnetic waves that describes the orientation of the oscillations constituent electric and magnetic fields. The wave I am investigating is light, whose polarization is described by stating the direction of its electric field. Because light is a transverse wave, its polarization is perpendicular to the direction in which it is travelling. The polarizer I will be using to convert unpolarized light (of mixed- polarization) into light with a single polarization state is Polaroid film. Polaroid film is an absorptive polarizer, which absorbs the unwanted polarization states of the mixed polarization light and transmits light of the required polarization.

Malus’ law states that when a perfect polarizer is placed in a beam of polarized light (e.g when two Polaroid films are crossed), the intensity, I, of the transmitted light is given by:

[pic]

In this case where: [pic] is the intensity of the light after passing the first Polaroid
[pic] is the angle between the Polaroids
In this experiment I aim to confirm Malus’ Law.

Hypothesis:

If there is an angle of 0º between the Polaroids they will both allow light polarized at the same angle through. As an example, let the first Polaroid be oriented in the vertical direction. 50% of the unpolarized light from the light source will be transmitted by the first polariod (since half of unpolarized light is made up of vertical components), and all of this will be transmitted by the second polaroid. If the are at 90º to...