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प्रश्न
Which property of soft iron makes it useful for preparing electromagnet?
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उत्तर
When a current is passed through an electromagnet's coil, it should become magnetic, but once the current is turned off, it should lose its magnetism. As a result, the ferromagnetic core (usually iron-based) used in an electromagnet should have high permeability and low retentivity, i.e. be magnetically'soft.'
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संबंधित प्रश्न
State any two advantages of electromagnets over permanent magnets.
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Magnetic meridian is
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A tangent galvanometer is connected directly to an ideal battery. If the number of turns in the coil is doubled the deflection will
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
Consider the situation of the previous problem. The directions of the magnetic field due to the dipole are opposite at
(a) P1 and P2
(b) Q1 and Q2
(c) P1 and Q1
(d) P2 and Q2
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(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
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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.
In a permanent magnet at room temperature ______.
Assertion: Electromagnetic are made of soft iron.
Reason: Coercivity of soft iron is small.
The relation b/w magnetic susceptibility xm and relativ~ permeability µr is
