Online Calculators since 2009
Welcome to our Physics lesson on Gauss Law for Magnetic Field, this is the first lesson of our suite of physics lessons covering the topic of Maxwell Equations, you can find links to the other lessons within this tutorial and access additional physics learning resources below this lesson.
As explained in tutorial 16.1 "Introduction to Magnetism", all magnets have two poles: one north and one south. The magnetic field lines are closes; they start from the north-pole and end at the south-pole of the same magnet. As and evidence for this, we can consider the shape the small iron filings poured on a paper sheet take when a magnet is placed below the sheet.
We have also provided (in the same tutorial) the definition of magnetic dipole, which is the smallest possible magnet made from a proton-electron pair. This means the magnetic monopoles do not exist.
The Gauss Law for the magnetic field implies that magnetic monopoles do not exist. Mathematically, this law means that the net magnetic flux Φm through any closed Gaussian surface is zero. The Gauss Law formula for magnetic field is
This outcome is different from the Gauss Law in electric fields. Recall that in electric fields, we have
Unlike in electric fields in which the net electric flux through a closed Gaussian surface is proportional to the charge, in magnetic field the net magnetic flux through a Gaussian surface is zero. This is because the net magnetic charge in all magnets is zero because the charge is balanced; in magnets, we simply have a certain regular alignment of dipoles but the net charge is zero.
The figure below gives a clearer idea on this point.
As you see from the figure, there are two lines entering the loop and two lines leaving the loop. Therefore, the net flux flowing through the Amperian loop is zero.
In which of the points shown in the figure
You have reached the end of Physics lesson 16.18.1 Gauss Law for Magnetic Field. There are 5 lessons in this physics tutorial covering Maxwell Equations, you can access all the lessons from this tutorial below.
|Tutorial ID||Physics Tutorial Title||Tutorial||Video|
|Lesson ID||Physics Lesson Title||Lesson||Video|
|16.18.1||Gauss Law for Magnetic Field|
|16.18.2||Induced Magnetic Fields|
|16.18.4||How to Find the Induced Magnetic Field?|
|16.18.5||Maxwell Equations Explained|
Enjoy the "Gauss Law for Magnetic Field" physics lesson? People who liked the "Maxwell Equations lesson found the following resources useful:
We hope you found this Physics lesson "Maxwell Equations" useful. If you did it would be great if you could spare the time to rate this physics lesson (simply click on the number of stars that match your assessment of this physics learning aide) and/or share on social media, this helps us identify popular tutorials and calculators and expand our free learning resources to support our users around the world have free access to expand their knowledge of physics and other disciplines.