Chemistry · Ch 10 — Halogen Derivatives
Plane polarized light
Plane polarized light
To understand optical activity (the next section), it is necessary first to understand plane polarised light. Ordinary light consists of electromagnetic waves whose electric and magnetic field oscillations occur in all possible planes perpendicular to the direction the light is travelling in -- that is, an ordinary light beam is a mixture of waves vibrating in every direction around its own axis of travel. When ordinary light is passed through a Nicol's prism (a device built from specially cut and arranged pieces of calcite, CaCO3, also called a polarizer), only the oscillations that happen to lie in one single plane are able to pass through and emerge from the other side; oscillations in every other plane are blocked. Light with oscillations confined to just one plane perpendicular to its direction of travel, pr …
Worked out. A Nicol prism (also called a polarizer) is a special type of prism built from carefully cut and cemented pieces of calcite, a crystalline form of calcium carbonate (CaCO3), arranged in a specific geometric manner so that only light oscillating in one particular plane is transmitted through it while light oscillating in other planes is blocked or deflected away. Passing ordinary light through a Nicol prism is the standard way plane polarised …
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your textbook's own diagram.
What the Nicol prism does. Ordinary light vibrates in every plane perpendicular to its direction of travel (left circle, arrows in all directions). After passing through a Nicol prism only one vibration plane survives (right circle, single vertical arrow) — this plane polarized lig …