Alternating Current — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Alternating Current.

RLC Series Circuit with Variable Frequency

high

Questions involving how current, impedance, or phase angle change as the frequency of the AC source is varied are very common. This tests the understanding of frequency dependence of $X_L$ and $X_C$, and the concept of resonance. A typical question might ask for the frequency at which current is maximum or minimum, or the phase difference at a specific frequency. Students should be prepared to analyze graphs of current vs. frequency or impedance vs. frequency.

Power Factor Correction

medium

While direct power factor correction problems are less frequent, understanding the concept of power factor and how to improve it (e.g., by adding a capacitor) is a slightly advanced but testable concept. Questions might ask about the conditions for unity power factor or the effect of adding a reactive component on the overall power factor of a circuit. This combines knowledge of RLC circuits with power concepts.

Transformer Efficiency and Losses

medium

Although transformers are a separate sub-topic, they are intrinsically linked to AC. Questions often involve calculating transformer efficiency, output power, or current, considering losses like eddy currents and hysteresis. This tests the practical application of AC principles and energy conservation. Students should know the ideal transformer equations and the sources of energy loss in real transformers.

Parallel AC Circuits (Conceptual)

low

While series RLC circuits are heavily emphasized, conceptual questions about parallel AC circuits might appear, especially regarding resonance in parallel circuits (anti-resonance, where impedance is maximum). Numerical problems on parallel circuits are generally beyond NEET scope, but understanding the basic difference in resonance conditions (current minimum at resonance) could be tested conceptually.