The magnetic field at perpendicular distance ' r ' from a long wire carrying current ' I ' is ' B '. The magnetic field at perpendicular distance ' 2r ' from the same wire is

Step-by-step solution

The magnetic field produced by a long straight wire carrying current I at a perpendicular distance r is given by: B = ₀ I 2 r This relation shows that the magnetic field is inversely proportional to the perpendicular distance from the wire: B 1 r Let the magnetic field at distance r₁ = r be B₁ = B . Let the magnetic field at distance r₂ = 2r be B₂ . Taking the ratio of the magnetic fields: B₂ B₁ = r₁ r₂ B₂ B = r 2r B₂ B = 1 2 B₂ = B 2