Magnetism and matter Flashcards
weber / metre^2 is the unit of
magnetic field intensity
{ another unit is N A^-1 m^-1 }
a magnetic needle is placed in a non uniform magnetic field. it will experience
a force and a torque
Nickel is an example of
a ferro magnetic substance
_____ substances have small positive magnetic susceptibility
paramagnetic substances
SI unit of pole strength
SI unit of magnetic moment
ampere x metre
ampere x metre^2
the diamagnetic substances are ________from strong magnets
repelled
when the paramagnetic substances are suspended freely in a magnetic field they align themselves ______to the field
parallel
can a magnet exist without poles
yes. toroid
Substance having magnetic susceptibilty i) 4/5 is
ii) -0.5 is
Paramagnetic substance.
diamagnetic substance.
Define effective length of a magnet
the distance b/w magnetic poles of a magnet
DEFINE MAGNET
A magnet is defined as
An object which is capable of producing magnetic field and attracting unlike poles and repelling like poles.
PROPERTIES OF MAGNETIC LINES
(i) The magnetic field lines of a magnet (or a solenoid) form continuous closed loops
Its direction from a positive charge and end on the negative charge or escape to infinity
(ii) The tangent to the field line at a given point represents the direction of the net magnetic field B at that point.
(iii) The larger the number of field lines crossing per unit area, the stronger is the magnitude of the magnetic field B.
(iv) The magnetic field lines do not intersect, for if they did, the direction of the magnetic field would not be unique at the point of
intersection
Bar magnet as an equivalent
solenoid
Cutting a bar magnet in
half is like cutting a solenoid. We get two smaller solenoids with weaker magnetic properties.
The magnetic potential energy Um is given by
–m.B
gauss law of magnetism
Gauss’s law for magnetism states that the magnetic flux B across any closed surface is zero; that is, B = 0,
