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

Explanation

### Step-by-Step Solution:

1. **Understanding Polarization**:
- Polarization is the process by which light waves are filtered based on their orientation. A polarizer allows light waves of a certain orientation to pass through while blocking others. When two polarizers are crossed (i.e., their axes are perpendicular), no light passes through them.

2. **Initial Condition with Transparent Plastic**:
- When a sheet of transparent plastic is placed between two crossed polarizers, it does not transmit any light. This is because the plastic is not a polarizer and does not align the light waves in any specific direction. Thus, the light that passes through the first polarizer is blocked by the second one.

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