Question

An infinitely long, solid, cylindrical conductor has a radius of 1 meter and is surrounded by air. It carries current out of the page. The current density J inside the conductor varies with radial distance from the central axis according to J(r) = 5r^2 where r is in meters and J is in Amps per square meter. (worth 10% of exam) Find the magnitude of the magnetic field at point A, situated inside the conductor at a distance of 50 cm from the central axis of the conductor. 1.55 Times 10^-7 T 1.96 Times 10^-7 T 2.36 Times 10^-7 T 2.75 Times 10^-7 T 3.10 Times 10^-7 T 3.53 Times 10^-7 T 4.11 Times 10^-7 4.67 Times 10^-7 T (worth 10% of exam) Find the magnitude of the magnetic field at point B, situated outside the conductor at a distance of 150 cm from the central axis of the conductor. 1.05 Times 10^-6 T

Answer: 3. (I) b (II) a

Answer 1

The magnetic field insi de a circular region (r <R)is, μ군 The rel ati on between the current density and current 1s, i,- JA Then for (Here, J,-5,2 = 5(0.50m)) (47×10-7 T/mA)(5(0.50m)2)(0.50 m) -3.9x10-7T Correct answer approximately (f) The magnetic field outsi de the circular region is The rel ati on between the current density and current is i, - JA Then = A -29 (Here, Ja = 5,2 2r r from center of sphere is r=150 cm=1.50 m 2 (47×10-7 T/m. A)(5(1.50m)2)(1.0 m) B 2(1.50m) = 4.7 × 10-6T 5.0x10T