Q15DQ - University Physics with Modern Physics

Question

When a sheet of plastic food wrap is placed between two crossed polarizers, no light is transmitted. When the sheet is stretched in one direction, some light passes through the crossed polarizers. What is happening?

Step-by-Step Solution

Answer

The sheet becomes a polarizer when it is wrapped then stretched.

Step 1: Definition of polarizer

A polarizer is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations or one can say polarizer as a purely optical device that can convert a beam of unpolarized light into one that is appreciably polarized in some form.

Step 2: Determine why some light passes when sheet is stretched

When the sheet is wrapped, it blocks the light but when it is stretched again, its parts are aligned in one direction. In this case, it acts as a polarizer and transmits light in one direction.

Hence, wrapping the sheet then stretching it makes it a polarizer that causes the light to be transmitted.