How is magnetic flux density related to current in a conductor?

Magnetic flux density in a conductor is directly proportional to the current flowing through it.

In more detail, the relationship between magnetic flux density (B) and current (I) in a conductor is governed by Ampere's Law. This law states that the magnetic field created by an electric current is proportional to the size of that current with a constant of proportionality equal to the permeability of free space. The equation is B = μ0I/2πr, where B is the magnetic flux density, μ0 is the permeability of free space, I is the current, and r is the distance from the wire.

The magnetic field around a conductor due to a current flowing through it is always circular. The direction of the magnetic field is given by the right-hand grip rule. If you grip the conductor in your right hand with your thumb pointing in the direction of the current, your fingers will curl around the conductor in the direction of the magnetic field.

For a foundational understanding of magnetic fields, explore the basics of magnetic fields.

The strength of the magnetic field decreases as you move further away from the conductor. This is represented by the 'r' in the denominator of the equation. The magnetic field is strongest close to the conductor and decreases with increasing distance from the conductor.

Understanding how a magnetic field is generated by current can deepen comprehension of the principles discussed here.

The permeability of free space, μ0, is a constant that represents how much a magnetic field can permeate through space. It has a value of 4π x 10^-7 T m/A. The higher the permeability, the more a material can conduct a magnetic field.

Additionally, the concept of electromagnetic induction is a crucial next step for those interested in the dynamic interactions between electric currents and magnetic fields.

IB Physics Tutor Summary: Magnetic flux density, which measures the strength of a magnetic field in a conductor, is directly linked to the current flowing through it, as described by Ampere's Law. This law shows that the magnetic field's intensity increases with higher current and decreases further away from the conductor. The relationship is summarized by the formula B = μ0I/2πr, highlighting the key factors affecting magnetic field strength.