Two polarizing sheets are placed together with their transmission axes crossed so that no light is transmitted. A third sheet is inserted between them with its transmission axis at an angle of` 45^@` with respect to each of the other axes. Find the fraction of incident unpolarized light intensity transmitted by the three sheet combination.

Explanation

To solve the problem of finding the fraction of incident unpolarized light intensity transmitted by the combination of three polarizing sheets, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Initial Setup**:
- We have two polarizing sheets (let's call them P1 and P2) placed with their transmission axes crossed. This means that no light can pass through them when they are placed directly against each other.

2. **Inserting the Third Sheet**:
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