Same chapter3 marksDifficulty: Medium
What is an equipotential surface? State two of its properties.
Electrostatics
3 marksDifficulty: Medium
State Gauss's theorem and use it to find the field of an infinite line of charge.
Original Khojo Papers practice question — not from a past board paper.
Answer
Gauss's theorem states that the total electric flux through any closed surface equals 1/ε0 times the charge enclosed. Taking a coaxial cylinder of radius r and length l round a line of linear charge density λ, the flux is E × 2πrl and the enclosed charge is λl, so E = λ/2πε0r.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The field of a line charge therefore falls off as 1/r, not as 1/r2.
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