The magnetic polarization results in a bound current $J_b$
(A) which is associated with magnetization of the material.
(B) which involves spin and orbital motion of electrons.
(C) which is the result of linear motion of charge when electric polarization changes.
(D) which is given by $ \vec \nabla \times \vec M $ (where $\vec M$ is magnetization).
Choose the correct answer from the options given below:
Understanding Magnetic Polarization and Bound Current
This question explores the nature of bound currents that arise during magnetic polarization. Magnetic polarization refers to the process by which a material acquires magnetization when subjected to an external magnetic field. Let's analyze each statement to determine its validity:
Statement (A) Analysis: Association with Magnetization
Statement (A) claims that the bound current is associated with the magnetization of the material. This is correct. Magnetization ($\vec M$) is the fundamental property that describes how a material responds to a magnetic field, representing the magnetic dipole moment per unit volume. The bound currents are microscopic currents within the material that create this net magnetization.
Statement (B) Analysis: Electron Motion
Statement (B) states that the bound current involves the spin and orbital motion of electrons. This is also correct. The magnetic properties of materials originate from the quantum mechanical property of electron spin and the classical concept of electron orbital motion around atomic nuclei. These motions create tiny magnetic dipole moments, and their alignment leads to magnetization and bound currents.
Statement (C) Analysis: Relation to Electric Polarization
Statement (C) suggests the bound current results from the linear motion of charge when electric polarization changes. This statement describes the bound currents related to electric polarization, not magnetic polarization. Electric polarization involves the separation or alignment of electric charges, leading to bound surface charges and conduction currents related to electric fields, while magnetic polarization deals with magnetic dipoles and currents related to magnetic fields. Therefore, this statement is incorrect in the context of magnetic polarization.
Statement (D) Analysis: Formula for Bound Current
Statement (D) provides a formula for the bound current density: $ \vec J_b = \vec \nabla \times \vec M $. This is a standard result in magnetism and electromagnetism. It signifies that the magnetic bound current density is proportional to the curl of the magnetization vector. This formula effectively captures how the alignment of microscopic magnetic moments (magnetization) creates circulating currents that can be viewed macroscopically.
Conclusion on Correct Statements
Based on the analysis:
- Statement (A) is correct.
- Statement (B) is correct.
- Statement (C) is incorrect.
- Statement (D) is correct.
Therefore, the correct statements are (A), (B), and (D).
Final Answer Selection
The option that includes only the correct statements (A), (B), and (D) is the correct choice.
Important Questions from Miscellaneous
- Which of the following scheduler/schedulers is/are also called CPU scheduler ?
(A). Short Term Scheduler
(B). Long Term Scheduler
(C). Medium Term Scheduler
(D). Asymmetric Scheduler
Choose the correct answer from the options given below: - A situation where two or more processes are blocked, waiting for resources held by each other is called:
- External fragmentation occurs ________.
- Which disk scheduling algorithm looks for the track closest to the current head position?
- Which CPU scheduling algorithm prefers the process with the shortest burst time?
