Topic: Ampere's law: straight wire and solenoid· Magnetic Effects of Current and Magnetism

A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field, B with the distance, d, from the centre of the conductor, is correctly represented by the figure :

A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field, B with the distance, d, from the centre of the conductor, is correctly represented by the figure :

four B vs d graphs (options 1-4)

1. [graph] B constant (flat) for d < R, then decreasing for d > R

2. [graph] B zero for d < R, jumps to maximum at R then decreasing for d > R

3. [graph] B increasing linearly for d < R, peak at R, then decreasing for d > R

4. [graph] B increasing linearly for d < R, then constant for d > R

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Answer: 3. [graph] B increasing linearly for d < R, peak at R, then decreasing for d > R

By Ampere's law for a cylindrical conductor with uniform current density:

Inside (\(d
Outside (\(d>R\)): \(B=\dfrac{\mu_0I}{2\pi d}\), decreasing as \(1/d\).

The field is maximum at \(d=R\). This is graph 3.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field, B with the distance, d, from the centre of the conductor, is correctly represented by the figure :

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