Magnetic effects of current Test - 1

As the magnetic needle is broken into the two halves from the middle, so the pole strength of the magnetic needle will remain the same. Distance between the two poles becomes halved, so the magnetic moment will become half as magnetic moment is given by the product of the pole strength and the separation between the poles, M = mL

When L' = L/2,
M' = mL/2 = M/2

As we know, the magnetic field is produced by the current carrying wire or we can say the source of the magnetic field is current. An accelerated charge, decelerated charge or a charge in uniform motion produce the current whereas the stationary charge produces an electric field.

No current will be induced as there is no change in the magnetic flux linked with coil.

Diamagnetic substances are those which are repelled by magnets, and when placed in a non-uniform magnetic field move from stronger to weaker part of the field. Familiar examples of these are bismuth, phosphorus, antimony, copper, water, alcohol and hydrogen.

Electromagnets are used to turn on and off. This is opposed to permanent magnets that are desired to remain magnetic all the time. Low coercivity means that it requires low magnetic field and, thus, low opposite current to bring it back to the non-magnetic state. Low retentivity means that it becomes a weak magnet when the current is turned off, ideally zero retentivity. All of these features are necessary for the typical application: pick up iron-like metals while the current is on and drop them when the current is off.

The two current-carrying conductors attract each other when the currents are in the same direction and repel each other when the currents are in opposite directions.

The two wires experience force in the direction according to Fleming's left hand rule.