PREVIOUS LESSON NEXT LESSON
We now turn our attention to a very important principle that underpins much of what follows - moving chrage generate magnetic fields.
In the early 1800s scientists were intrigued by the fact that a wire carrying an electrical current would cause a compass needle to deflect. It was Michael Faraday who established that magnetic fields, which he described as lines of force, were circular.
We now know that it is actually the charges themselves, namely the electrons, that generate magnetic fields due to their motion.
This video looks at the relationship between current and the magnetic field it generates
In the early 1800s scientists were intrigued by the fact that a wire carrying an electrical current would cause a compass needle to deflect. It was Michael Faraday who established that magnetic fields, which he described as lines of force, were circular.
We now know that it is actually the charges themselves, namely the electrons, that generate magnetic fields due to their motion.
This video looks at the relationship between current and the magnetic field it generates
Check your understanding
Interactive
The following interactive is self explanatory (by Walter Fendt)
The following interactive is self explanatory (by Walter Fendt)
Ampere's Law application - the solenoid
So how does a straight wire with a circular magnetic field get used to make an electromagnet, or a solenoid? This video looks at the physics.
So how does a straight wire with a circular magnetic field get used to make an electromagnet, or a solenoid? This video looks at the physics.
Going Deeper
The following activity is more related to the magnetic field around a wire, or more specifically the magnetic field between two wires.
This Desmos activity allow you to see qualitatively the strength of the field between (and on either side) two wires. The wires are the asymptotes of the graph represents the wires
By sharing the current (which can be reversed by making them negative) you effectively see if there are places that exist where the B field is zero, andwhee they are a minimum
the 'k' value represents µ/2π though( its value isn't that large) and can be left alone. Changing it does not change the trend of the graph
The derivative is shown to show that a minimum can exist ate certain points
The following activity is more related to the magnetic field around a wire, or more specifically the magnetic field between two wires.
This Desmos activity allow you to see qualitatively the strength of the field between (and on either side) two wires. The wires are the asymptotes of the graph represents the wires
By sharing the current (which can be reversed by making them negative) you effectively see if there are places that exist where the B field is zero, andwhee they are a minimum
the 'k' value represents µ/2π though( its value isn't that large) and can be left alone. Changing it does not change the trend of the graph
The derivative is shown to show that a minimum can exist ate certain points
