View source for Fleming's right-hand rule

{{Short description|Mnemonic for the direction of induced current in a moving magnetic field}}
[[Image:RightHandOutline.png|Fleming's right hand rule|thumb|400px]]

In [[electromagnetism]], '''Fleming's right-hand rule'''  (for [[Electric generator|generators]]) shows the direction of [[induced current]] when a [[Electrical conductor|conductor]] attached to a circuit moves in a [[magnetic field]].  It can be used to determine the direction of current in a generator's windings.

When a conductor such as a wire attached to a circuit moves through a magnetic field, an [[electric current]] is induced in the wire due to [[law of induction]]. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows.

The right hand is held with the [[thumb]], [[index finger]] and [[middle finger]] mutually perpendicular to each other (at right angles), as shown in the diagram.<ref>{{Cite book|title=Hughes Electrical & Electronic Technology|last=Hughes|first=Edward|date=5 April 2016|publisher=Pearson Education Limited|isbn=978-1-292-09304-8|edition=12th|pages=145}}</ref>

* The thu'''m'''b is pointed in the direction of the '''m'''otion of the conductor relative to the magnetic field.
* The '''f'''irst finger is pointed in the direction of the magnetic '''f'''ield. By convention, it's the direction from North to South magnetic pole.
* Then the se'''c'''ond finger represents the direction of the induced or generated '''c'''urrent within the conductor (from + to −, the terminal with lower [[electric potential]] to the terminal with higher electric potential, as in a voltage source)

The bolded letters in the directions above give a mnemonic way to remember the order. Another mnemonic for remembering the rule is the initialism "FBI", standing for '''F'''orce (or otherwise motion), '''B''' the symbol for the magnetic field, and '''I''' the symbol for current. The subsequent letters correspond to subsequent fingers, counting from the top: thumb → F; first finger → B; second finger → I.

There is also a [[Fleming's left-hand rule]] (for [[electric motors]]). The appropriately handed rule can be recalled from the letter "'''g'''", which is in "ri'''g'''ht" and "'''g'''enerator".

These [[mnemonic]]s are named after British engineer [[John Ambrose Fleming]], who invented them.

An equivalent version of Fleming's right-hand rule is the [https://i0.wp.com/www.mrsphysics.co.uk/higher/wp-content/uploads/2016/12/slap-rule.png?resize=300%2C253&ssl=1 left-hand palm rule].

== Distinction between the right-hand and left-hand rule ==
{{Excerpt|Fleming's left-hand rule for motors|Distinction between the right-hand and left-hand rule|only=paragraphs|hat=no}}

==See also==
*[[Right-hand rule]]
*[[Fleming's left-hand rule for motors]]

== References ==
<references />

==External links==
* [http://micro.magnet.fsu.edu/electromag/electricity/generators/index.html Diagrams at magnet.fsu.edu]
* [https://www.teachoo.com/10703/3113/Fleming-s-Right-Hand-Rule/category/Concepts/ Diagrams and exercises]

[[Category:Science mnemonics]]
[[Category:Electromagnetism]]

[[zh:佛來明右手定則]]