A bar magnet is oscillating in the earth’s magneticfield with a period T. What happens to its periodof motion, if its mass is quadrupled [1994, 03]
The work done in turning a magnet of magneticmoment M by an angle of 90° from the meridian,is n times the corresponding work done to turnit through an angle of 60°. The value of n isgiven by [1995]
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For protecting a sensitive equipment from theexternal electric arc, it should be [1998]
If a diamagnetic substance is brought near northor south pole of a bar magnet, it is [1999]
A bar magnet, of magnetic moment , is placed in a magnetic field of induction . The torque exerted on it is
Current i is flowing in a coil of area A and number of turns N, then magnetic moment of the coil, M
is [2001]
Two magnets of magnetic moments M and 2M are placed in a vibration magnetometer, with theidentical poles in the same direction. The timeperiod of vibration is T1. If the magnets areplaced with opposite poles together and vibratewith time period T2, then [2002]
A diamagnetic material in a magnetic field moves
According to Curie’s law, the magnetic susceptibilityof a substance at an absolutetemperature T is proportional to [2003]
A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that is in the plane of the coil. If due to a current i in the triangle a torque τ acts on it, the side l of the triangle is [2005]
If the magnetic dipole moment of an atom ofdiamagnetic material, paramagnetic material andferromagnetic material are denoted by μd, μp andμf respectively, then [2005]
Above Curie temperature [2006]
Nickel shows ferromagnetic property at roomtemperature. If the temperature is increasedbeyond Curie temperature, then it will show [2007]
Curie temperature is the temperature abovewhich [2008]
A bar magnet having a magnetic moment of 2× 104 JT–1 is free to rotate in a horizontal plane.A horizontal magnetic field B = 6 × 10–4 T existsin the space. The work done in taking the magnetslowly from a direction parallel to the field to a direction 60° from the field is [2009]
If a diamagnetic substance is brought nearthe north or the south pole of a bar magnet, itis: [2009]
A vibration magnetometer placed in magneticmeridian has a small bar magnet. The magnetexecutes oscillations with a time period of 2 secin earth's horizontal magnetic field of 24 microtesla. When a horizontal field of 18microtesla is produced opposite to the earth'sfield by placing a current carrying wire, the newtime period of magnet will be [2010]
Electromagnets are made of soft iron because soft iron has [2010]
Two identical bar magnets are fixed with their centres at a distance d apart. A stationary charge Q is placed at P in between the gap of the two magnets at a distance D from the centre O as shown in the Figure
The force on the charge Q is
The magnetic moment of a diamagnetic atom is
[2010]
There are four light–weight–rod samples A,B,C,D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted [2011]
(i) A is feebly repelled
(ii) B is feebly attracted
(iii) C is strongly attracted
(iv) D remains unaffected
Which one of the following is true ?
A short bar magnet of magnetic moment 0.4J T–1 is placed in a uniform magnetic field of 0.16 T. Themagnet is in stable equilibrium when the potentialenergy is [2011M]
A compass needle which is allowed to move in ahorizontal plane is taken to a geomagnetic pole.It : [2012]
A magnetic needle suspended parallel to a magnetic field requires √3 J of work to turn it through 60°. The torque needed to maintain the needle in this position will be : [2012M]
A bar magnet of length ‘ℓ’ and magnetic dipole moment ‘M’ is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be [NEET 2013]
A bar magnet of magnetic moment M is placed atright angles to a magnetic induction B. If a force F is experienced by each pole of the magnet, thelength of the magnet will be [NEET Kar. 2013]
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