Concept:Dynamic (or AC) resistance represents the opposition offered by the diode to a small AC variation in voltage. It is defined as the reciprocal of the slope of the \(I\)-\(V\) characteristic curve at a given operating point (Q-point).
Formula:$$r_d = \frac{\Delta V}{\Delta I} = \frac{d V}{d I}$$
Solution:- Static (DC) resistance is \(R_{\text{dc}} = \frac{V}{I}\).
- Dynamic (AC) resistance is \(r_{\text{ac}} = \frac{\Delta V}{\Delta I}\), which is the inverse slope (\(1 / \text{slope}\)) of the \(I\) vs \(V\) plot.
Why other options are incorrect:- Option A: The ratio \(V/I\) defines static (DC) resistance, not dynamic resistance.
- Option B: The product \(V \times I\) calculates instantaneous power dissipation.
- Option D: This mathematical formula has no physical meaning in diode circuit analysis.
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