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Why is It Not Possible to Make Permanent Magnets from Paramagnetic Materials? - Physics

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प्रश्न

Why is it not possible to make permanent magnets from paramagnetic materials?

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उत्तर

Permanent magnets are made from the material that are easily magnetized and retain the magnetization even reverse magnetizing field is applied (high coercivity). Paramagnetic materials get small magnetization, if they are placed in magnetic field, they lose their magnetization easily if the reverse field is applied. Hence, they are not used to make permanent magnet.

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पाठ 15: Magnetic Properties of Matter - Short Answers [पृष्ठ २८५]

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एचसी वर्मा Concepts of Physics Vol. 2 [English] Class 11 and 12
पाठ 15 Magnetic Properties of Matter
Short Answers | Q 5 | पृष्ठ २८५

संबंधित प्रश्‍न

What are permanent magnets? Give one example ?


Write two characteristics of a material used for making permanent magnets ?


Why is the core of an electromagnet made of ferromagnetic materials?


Magnetic meridian is


Which of the following four graphs may best represent the current-deflection relation in a tangent galvanometer?


A very long bar magnet is placed with its north pole coinciding with the centre of a circular loop carrying as electric current i. The magnetic field due to the magnet at a point on the periphery of the wire is B. The radius of the loop is a. The force on the wire is


To measure the magnetic moment of a bar magnet, one may use

(a) a tangent galvanometer
(b) a deflection galvanometer if the earth's horizontal field is known
(c) an oscillation magnetometer if the earth's horizontal field is known
(d) both deflection and oscillation magnetometer if the earth's horizontal field is not known


Do permeability and relative permeability have the same dimensions?


The desirable properties for making permanent magnets are _________________ .


The coercive force for a certain permanent magnet is 4.0 × 104 A m−1. This magnet is placed inside a long solenoid of 40 turns/cm and a current is passed in the solenoid to demagnetise it completely. Find the current.


The magnetic field due to the earth has a horizontal component of 26 μT at a place where the dip is 60°. Find the vertical component and the magnitude of the field.


A magnetic needle is free to rotate in a vertical plane which makes an angle of 60° with the magnetic meridian. If the needle stays in a direction making an angle of `tan^-1(2sqrt(3))` with the horizontal, what would be the dip at that place?


The needle of a dip circle shows an apparent dip of 45° in a particular position and 53° when the circle is rotated through 90°. Find the true dip.


A moving-coil galvanometer has a 50-turn coil of size 2 cm × 2 cm. It is suspended between the magnetic poles producing a magnetic field of 0.5 T. Find the torque on the coil due to the magnetic field when a current of 20 mA passes through it.


A short magnet oscillates in an oscillation magnetometer with a time period of 0.10 s where the earth's horizontal magnetic field is 24 μT. A downward current of 18 A is established in a vertical wire placed 20 cm east of the magnet. Find the new time period.


A bar magnet makes 40 oscillations per minute in an oscillation magnetometer. An identical magnet is demagnetized completely and is placed over the magnet in the magnetometer. Find the time taken for 40 oscillations by this combination. Neglect any induced magnetism.


Which property of soft iron makes it useful for preparing electromagnet?


What should be retentivity and coercivity of permanent magnet?


Permanent magnets are the substances having the property of ______.

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