A long solid cylindrical conductor of radius R carries total current I uniformly over its cross-section. Find the magnetic field at distance r<R from the axis.
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A long solid cylindrical conductor of radius R carries total current I uniformly over its cross-section. Find the magnetic field at distance r<R from the axis.

G1 Physics · Accepted Answer

The enclosed current is I(r²/R²). Ampere's law gives B(2πr)=μ₀I r²/R², hence B=μ₀Ir/(2πR²).