Part A A wire of radius 0.7 cm carries a current of 100 A that is uniformly dist

Question

Part A

A wire of radius 0.7 cm carries a current of
100 A that is uniformly distributed over its
cross-sectional area.
The permeability of free space is 4 ×
107 T · m/A.
Find the magnetic field at a distance of
0.4 cm from the center of the wire.
Answer in units of T.


I am using the formula B=I/2d. At first I came up with .005T, but then realized I should have been using .007m instead of .004m. My second answer was .002857T using the radius value and that was also wrong. Am I using the wrong formula?

Part B

Find the magnetic field at the surface of the wire (in T).

Part C

Find the magnetic field at a point outside the
wire 0.2 cm from the surface of the wire. (in T)

Explanation / Answer

Radius of the wire is R = 0.7 cm current in the wire is I = 100A    Magnetic field at a distance r = 0.4 cm from the center of the wire is                B = _0 i / 2R^2 * r                   = 4*10^-7 *100A / 2* ( 0.7*10^-2m)^2 * ( 0.4*10^-2m)                  = 1.63*10^-3 T b ) Magnetic field at the surface of the wire is            B = _0 i / 2R                = 4*10^-7 * 100A / 2 * 0.7 *10^-2 m                = 2.85*10^-3 T c ) magnetic field at a point out side the wire is 0.2cm           B = _0 i / 2r   where r = 0.7+ 0.2 = 0.9cm              = 4*10^-7 * 100A / 2 * 0.9 *10^-2 m              = 2.22*10^-3 T

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.