Question
Download Solution PDFWhen a bar is subjected to a rapidly alternating magnetic field, there is rapid extension and contraction in the length of the bar. This phenomenon is known as
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UPSC ESE Electronics & Communication 2022 Official Paper
Answer (Detailed Solution Below)
Option 3 : magnetostriction
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ST 1: UPSC ESE (IES) Civil - Building Materials
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- Magnetostriction is a property of ferromagnetic materials which causes them to expand or contract in response to a magnetic field. This effect allows magnetostrictive materials to convert electromagnetic energy into mechanical energy. As a magnetic field is applied to the material, its molecular dipoles and magnetic field boundaries rotate to align with the field. This causes the material to strain and elongate
Additional Information
- Magnetic saturation is the state reached in a sample when increases in applied external magnetic field H cannot increase the magnetization of the material further. At saturation, the total magnetic flux density B does not increase with increases in applied external fields.
- Diamagnetism is a phenomenon common to all materials. Any moving charge, including orbital electrons, experiences a force (known as the Lorentz force) in a magnetic field B. This Lorentz force deflects the path of electrons in such a way that they process clockwise about B (when viewed along a line in the direction of B). This is equivalent to a current anticlockwise about B, which produces a negative induced magnetic moment known as diamagnetism. Thus, the susceptibility is negative and very small, typically on the order of 10−5.
- Magnetic hysteresis is an important phenomenon and refers to the irreversibility of the magnetisation and demagnetisation process. When a material shows a degree of irreversibility it is known as hysteretic.
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