A diamagnetic substance is a material that creates an opposing magnetic field when exposed to an external magnetic field. This means that diamagnetic substances are repelled by magnets. Here's why:
1. Nature of Diamagnetism: Diamagnetic materials have no unpaired electrons, and their atomic moments generally cancel out. When placed in a magnetic field, they develop an induced magnetic moment that opposes the applied field.
2. Response to Magnetic Poles: Due to their opposition to the applied magnetic field, diamagnetic substances are repelled by both the north and south poles of a magnet. This is because they tend to move from stronger to weaker parts of the magnetic field.
3. Experimental Observation: When a diamagnetic substance is brought near a bar magnet, it experiences a force that pushes it away from both poles.
Considering the behavior of diamagnetic materials, the correct answer is: "repelled by north pole as well as by south pole".
A short bar magnet placed with its axis at 30º with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 × 10-2 J. What is the magnitude of magnetic moment of the magnet?
A short bar magnet of magnetic moment m = 0.32 J T-1 is placed in a uniform magnetic field of 0.15 T. If the bar is free to rotate in the plane of the field, which orientation would correspond to its ( a ) stable, and ( b) unstable equilibrium? What is the potential energy of the magnet in each case?
A closely wound solenoid of 800 turns and area of cross section 2.5 × 10-4 m2 carries a current of 3.0 A. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment?