Practice portal › Moving Charges and Magnetism › Biot-Savart Law: Straight Wires and Arcs
Asked in CBSE PMT 1992 · Straight wire segments
Idea: outside a long straight wire, B=(μ₀i)/(2π r), so B∝1/r.
(B₂)/(B₁)=(r₁)/(r₂)=r/(2r)=1/2.
B₂=(B₁)/2.
B₂=(0.4)/2.
B₂=0.2 T.
A long wire is a one-dimensional source, which is why its field falls only as 1/r rather than as 1/r².
Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.
Practise this with a timer