For a circular loop of radius 1 m, at what distance from its centre on the axis is the magnetic field equal to 1/(2√2) times the field at the centre?
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For a circular loop of radius 1 m, at what distance from its centre on the axis is the magnetic field equal to 1/(2√2) times the field at the centre?

G1 Physics · Accepted Answer

On the axis of a loop, B(z)/B(0)=[R²/(R²+z²)]^(3/2). With R=1 m and ratio 1/(2√2)=1/2^(3/2), we get 1+z²=2, so z=1 m. Hence A.