# Magnetism and Matter: Dipole Moment of a Magnet, Gauss՚s Law for Magnetism (For CBSE, ICSE, IAS, NET, NRA 2022)

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• Many of us also want to know about the interstellar space and its weak magnetic field.
• We will find out the magnitude of the magnetic moment of a magnet with a certain degree of the uniform magnetic field and what will happen if the magnet is rotated freely in a plane and what will be the potential energy of the magnet.
• How much torque is required for turning a magnet so that its magnetic moment is at a certain alignment with the field?
• We will be seeing an example of a magnetic needle used to find out magnetic meridian points and computing the direction and magnitude of the earth՚s magnetic field.
• There are various examples, exemplary question, MCQ՚S and worksheets mentioned below which will help you understand magnetism and the magnetic field with its uses and application

## Dipole Moment of a Magnet

The Magnetic Dipole Moment of a Magnetic Dipole is Given by Where, M is Pole Strength and is Dipole Length Directed from s to N.

• When a magnet is experiencing a dipole moment m, and it is placed in a uniform magnetic field B, then it experiences:
• The force on it as zero
• The torque on it as
• The potential energy can be said to be as - . Where the zero of energy is determined when m is perpendicular to B

## Gauss՚s Law for Magnetism

• This law of magnetism points out the fact that the net magnetic flux through any surface which is closed tends to be Zero.
• Gauss՚s law for magnetism is one of the four Maxwell՚s equations that underlie classical electrodynamics.
• It states that the magnetic field B has divergence equal to zero, in other words, that it is a solenoidal vector field.
• It is equivalent to the statement that magnetic monopoles do not exist.
• The intensity of a magnetic field, measured in Gauss or Teslas (10,000 Gauss = 1 Tesla) , is also a common measurement of a magnets strength as this is a representation of the density of a magnetic field produced by a magnet, known as flux density.

## Components of the Earth՚s Magnetic Field

• Three components have to be taken care of in order to particularise the earth՚s magnetic field:
• The horizontal component
• Magnetic Dip
• Magnetic Declination