Concept:An ideal diode acts as a perfect electrical switch: it behaves as a closed switch (short circuit, \(R_f = 0\), \(V_D = 0\)) when forward biased and as an open switch (open circuit, \(R_r = \infty\), \(I_r = 0\)) when reverse biased.
Formula:$$R_{\text{forward, ideal}} = 0, \quad R_{\text{reverse, ideal}} = \infty$$
Solution:- Forward Bias: Offers zero opposition to current flow (acts as a perfect conductor).
- Reverse Bias: Completely blocks all current (acts as a perfect insulator).
Why other options are incorrect:- Option B: Inverting the behavior describes a completely non-functional device, not an ideal diode.
- Option C: A constant resistance is an ohmic resistor, not a rectifying diode.
- Option D: Ideal diode models do not define temperature-dependent barrier infinities.
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