Physics 2 Marks Questions

The substance which on keeping in any magnetic field are slightly magnetized in the direction of the field and are attracted towards the ends of a powerful magnet when brought near it are known as paramagnetic substances and this property is known as Para magnetism.

Magnetic field lines are drawn with the help of iron fillings or magnetic needle. Four main characteristics are :
(1) More the number of force lines passing through a point, more strong will be magnetic field at that place.
(2) Two force lines never intersect each other.
(3) Tangent drawn at any point on the field lines gives the direction of magnetic field at that point.
(4) They are directed from north pole to south pole outside the magnet and inside the magnet, their direction is from south pole to north pole.

Those substances which on keeping in any magnetic field are attracted a bit towards the opposite side of the magnetic field and when brought near the ends of a powerful magnet are somewhat repelled, are known as diamagnetic substances. This property of these substances is known as diamagnetism. Examples are zinc (Zn), copper (Cu), silver (Ag), gold (Au) etc.

Magnetic susceptibility of paramagnetic substances (such as aluminium, calcium etc.) is positive and of diamagnetic substances (such as copper, lead etc.) is negative. Negative magnetic susceptibility exhibits that these substances are magnetised in opposite direction of external magnetic field.