8 Substances, which at room temperature, retain their ferromagnetic
property for a long period of time are called permanent magnets Physical quantity
Symbol
Nature
Dimensions
Units
Remarks
Permeability of
m0
Scalar
[MLT–2 A–2]
T m A–1
m0/4p = 10–7
free space
Magnetic field,
B
Vector
[MT–2 A–1]
T (tesla)
104 G (gauss) = 1 T
Magnetic induction,
Magnetic flux density
Magnetic moment
m
Vector
[L–2 A]
A m2
Rationalised 2023-24
151
Magnetism and
Matter
POINTS TO PONDER
1 A satisfactory understanding of magnetic phenomenon in terms of moving
charges/currents was arrived at after 1800 AD