A copper wire is wrapped 65 times around an unknown core of length 28cm. The current in the wire is 800mA and the magnetic field due to the electromagnet is 1.63 x 10-2T. What is the most likely material the wire is wrapped around?

Question

Adrian Ayala · Accepted Answer

Relative permeability #\mu_r# is 689 which is closer to the value for Manganes-Zinc Ferrite. So the core is likely made of Manganese-Zinc Ferrite.

Solenoid: The magnetic field strength #B#, inside a solenoid of length #l# made of #N# number of turns, carrying a current #i# and having a core made of a material with magnetic permeability #\mu=\mu_0\mu_r# is: #B = \mu(N/l)i# Given : #B=1.63 imes10^{-2}\quad T; \qquad i=0.8\quad A# #N/l = 65/(28 imes10^{-2} \quad m)=232.14m^{-1}# #\mu = \mu_0\mu_r = \frac{1.63 imes10^{-2}\quad T}{(232.14m^{-1})(0.8\quad A)}=8.77 imes10^{-5} \quad (T.m)/A# #\mu_r = \mu/\mu_0 = (8.77 imes10^{-5})/(4\pi imes10^{-7})=688.8# Wikipedia states that Manganese-Zinc Ferrite has a relative permeability of about 640, so it might be a Manganese-Zinc Ferrite core. I am grateful to Miroslav and A08 for correcting me on this. Materials with Magnetic Properties: https://tutor.hix.ai

Julia Aguilar · Answer

undefined The most likely material the wire is wrapped around is an iron core.