Problem 8 a A thin long wire carries a current of 5 A. Find the energy density o

Question

Problem 8 a A thin long wire carries a current of 5 A. Find the energy density of the magnetic field at a radial distance of 1.33 m from the wire. 2.249x10 J 3 b) Find the total energy stored in the magnetic field in a cylindrical annular region whose axis coincides with the wire ee figure). The inner radius of the cylindrical annulus is r 2 cm; the outer radius is R -29 cm and the length of the cylinder is 19 cm. You need to integrate the energy density over the given volume. Cylindrical coordinates will help Submit Answer Incorrect. Tries 116 Previous Tries

Explanation / Answer

eenrgy Density u = eenrgy/Volume = B^2/2uo

so

total energy integration of u = integ of B^2 V/(2uo)

u = (0.5 * uoI/2pi x)^2 * ( 2pi x dx L)/uo

u = ( uo I^2 L/ 4pi) * ln ( R/r)

so

Total eenrgy u = (4*3.14 *10^-7 * 5*5 * 0.19/(4*3.14)) * ln (0.29/0.12)

u = 4.2*10^-7 Joules

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---