Find out an example for dia-magnetic materials.
super conductors
alkali metals
ferrites
transition metals
When does a change occur to electromagnetic induction in a coil?
electric field intensity in the coil
magnetic field intensity in the coil
voltage in the coil
the coil's polarity
What is the basic source of magnetism?
Charged particles alone
Movement of charged particles
Magnetic dipoles
Magnetic domains
The induced voltage across a stationary conductor in a stationary magnetic field is
zero
reversed in polarity
increased
decreased
When does an iron rod become magnetic?
positive ions accumulate at one end and negative ions at the other end.
its atoms are aligned having plus charges on one side and negative charges on the other.
the net spins of its electrons are in the same direction.
its electrons stop moving and point in the same direction.
What is the main difference between electric charges and magnetic poles?
electric charges can be isolated, magnetic poles cannot be isolated
electric charges cannot be isolated, magnetic poles can be isolated
electric charges both attract and repel, magnetic poles only attract
electric charges both attract and repel, magnetic poles only repel
Magnet A has twice the magnetic field strength of magnet B, and at a certain distance pulls on the magnet B with a force of 100 N. What is the amount of force that magnet A exerts on magnet B ?
at or about 50 N
exactly 100 N
exactly 150N
More information is needed
The induced voltage across a coil with 250 turns that is located in a magnetic field that is changing at a rate of 8 Wb/s is
1000V
2000 V
31.25V
3125V
The ability of a material to remain magnetized after removal of the magnetizing force is known as
permeability
reluctance
hysteresis
retentivity
All pieces of iron have magnetic domains, why are most iron nails not magnetic?
they cannot conduct electricity
their domains are all oriented with respect to magnetic poles
their domains are randomly oriented, canceling out most magnetic forces
their atoms contain 4 electrons that spin magnetism is un-cancelled
