Concept:In an I-V graph (Current on the y-axis, Voltage on the x-axis), the slope of the curve at any point dictates the conductance. Resistance is the inverse of that slope.
Formula:$$ \text{Slope} = \frac{\Delta I}{\Delta V} = \frac{1}{R} $$
Solution:- Since Slope = \( 1/R \), if the resistance (\(R\)) is decreasing, the fraction \( 1/R \) must be increasing.
- An increasing slope means the curve must bend upwards, getting steeper towards the I-axis (current axis).
- Graph B correctly depicts an upward curving line (like a semiconductor/thermistor) where more current flows progressively easier as voltage increases.
Why other options are incorrect:- Opt A: Bending towards the V-axis means slope decreases, meaning Resistance is increasing (like a filament bulb).
- Opt C: Constant slope means Ohmic (constant resistance).
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