Explain the terms (i) stress, (ii) strain.

Explanation

### Step-by-Step Solution

**Step 1: Define Stress**
- Stress is defined as the force applied per unit area of a material. It can be mathematically expressed as:
\[ \text{Stress} (S) = \frac{\text{Force} (F)}{\text{Area} (A)} \]
- This definition indicates that stress is a measure of the internal resistance of a material to deformation when subjected to an external force.
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