Malus Law — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Malus Law.

Combined with Brewster's Law

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NEET often tests inter-topic connections. A question could involve light incident at Brewster's angle on a surface, then the reflected (polarized) light passes through an analyzer. This would require calculating the polarization angle from Brewster's Law ($n = an i_p$) and then applying Malus's Law. This adds a layer of complexity and checks multiple concepts simultaneously, making it a good candidate for a challenging question.

Graphical representation of intensity vs. angle

high

While direct numerical problems are common, NEET is increasingly incorporating graphical analysis. A question might present a graph of transmitted intensity versus the angle of rotation of an analyzer and ask students to identify the correct graph, interpret points on it (max/min intensity), or deduce the incident polarized intensity. This tests visual interpretation along with conceptual understanding of $I = I_0 cos^2 heta$ and its periodic nature.

Application in stress analysis (photoelasticity)

low

While photoelasticity is a direct application, it's generally considered a more advanced topic for undergraduate engineering physics. However, a simplified conceptual question could be framed, asking which principle explains how stress patterns become visible in transparent materials viewed through crossed polarizers. This would test the awareness of Malus's Law's broader applications without requiring complex calculations related to birefringence.

Intensity after a rotating polarizer

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A question could involve unpolarized light passing through a fixed polarizer, and then through a second polarizer that rotates at a constant angular speed $omega$. Students might be asked to find the average intensity transmitted over a full rotation or the instantaneous intensity as a function of time. This combines Malus's Law with basic rotational kinematics, adding a dynamic element to the problem.