Electrical Resistance — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Electrical Resistance.

Resistance of stretched/compressed wires

high

This is a classic problem type that tests understanding of both $R = \rho L/A$ and the principle of volume conservation. It requires a multi-step approach and is a good discriminator. Questions might involve calculating the new resistance when length is doubled, or when radius is halved, etc. The $n^2$ factor for length change is a key takeaway that is frequently tested.

Temperature dependence of resistance/resistivity

medium

Questions involving the formula $R_T = R_0 [1 + \alpha(T - T_0)]$ are common. Students might be asked to calculate the temperature coefficient ($\alpha$), the resistance at a new temperature, or the temperature at which resistance reaches a certain value. Comparisons between metals and semiconductors in terms of temperature dependence can also be asked conceptually.

Conceptual distinction between Resistance and Resistivity

high

NEET often tests fundamental definitions and distinctions. A question might ask which property is intrinsic to the material (resistivity) versus dependent on dimensions (resistance), or about their units. This checks for clarity in basic concepts, which is crucial for avoiding common misconceptions.

Ohmic vs. Non-Ohmic behavior and V-I graphs

medium

Understanding the difference between materials that obey Ohm's Law and those that don't, along with their characteristic V-I graphs, is a key conceptual point. Questions could involve identifying a V-I graph for a diode versus a metallic conductor, or listing examples of non-Ohmic devices.