A maintenance technician must demagnetize a steel tool chain that has become weakly…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A maintenance technician must demagnetize a steel tool chain that has become weakly magnetized during service. She winds a 200-turn coil uniformly over a straight 20cm section of the chain, forming an effective solenoid of radius 5.0cm. An alternating current of peak value 4.0A is initially supplied and then gradually reduced to zero over several minutes.
Answer the following.
(1) Determine the initial peak magnitude of the magnetic field at the center of the coil while the current is at its maximum value.
(2) Describe the step-by-step procedure the technician should follow to ensure the chain is effectively demagnetized as the current is reduced. Emphasize why small, gradual reductions are necessary.
(3) Explain, in terms of magnetic domains, how the alternating field with decreasing amplitude leads to demagnetization of the ferromagnetic chain.
(4) Identify two environmental factors other than an external magnetic field that could later cause the chain to regain some magnetization, and explain the physical mechanisms involved.