CBSE Class 12 Physics 2025 — Independently Prepared Solutions
In-depth mathematical and conceptual solutions for CBSE Class 12 Physics 2025 Board Examination (Code 55/1/1), focusing on Gauss's Law, electromagnetic induction, AC circuits, and wave optics derivations.
Solutions and conceptual explanations are independently prepared by QuizCluster. QuizCluster is an independent educational platform and is not affiliated with, endorsed by, or sponsored by the Central Board of Secondary Education (CBSE). Official question papers are accessed via direct external links to official CBSE repositories and are never hosted or mirrored on QuizCluster.
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Q1 of 33Practice chapter-wise adaptive MCQs to strengthen weak concepts from this board paper.
View all years for this subjectElectric Flux & Gauss's Law in Electrostatics
Step 1: Total flux by Gauss's Law
According to Gauss's Law, the total electric flux Φ_total through any closed surface is equal to 1/ε₀ times the net charge enclosed within that surface: Φ_total = q_enclosed / ε₀ = q / ε₀.
Step 2: Symmetry analysis of the cube
A cube possesses 6 identical faces. Since the point charge is situated at the exact geometric center, the flux is distributed symmetrically across all 6 faces. Therefore, the flux through any single face is: Φ_face = (1/6) · Φ_total = q / (6 ε₀).
- Gauss's Law: ∮ E · dA = q_enclosed / ε₀
- Symmetry rule for n faces: Φ_single_face = Φ_total / n
Electric flux depends solely on the enclosed charge and permittivity of free space, completely independent of the dimensions of the Gaussian surface.
Writing q / ε₀ without dividing by 6 for a single face.
Source of question paper: Central Board of Secondary Education (CBSE). QuizCluster provides independently prepared educational solutions and explanations. QuizCluster is an independent educational platform and is not affiliated with or endorsed by CBSE. Question papers are accessed through links to official CBSE resources and are not hosted by QuizCluster.