Magnetic force follows the right-hand rule, for open palm: the thumb shows current $I$, magnetic field $B$ penetrates open palm, force $F$ acts in the direction of fingers. Magnetic poles are denoted as: N - north, S - south. The force is proportional to the length $l$ of wire exposed to the magnetic field.
In this version (with the open palm), the following mnemonic can be used to make it easier to remember:
- Force F acts in the direction of the straight “Fingers
- the symbol for current is I which looks similar to a single thumb
- the symbol for flux density is B which is has some similarity to P as in oPen Palm
However - the same relationship between the directions can be shown by different configurations of right or left hand, as shown below.
right-hand_rule_left-hand_rule_single_wire_e-m.png
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S. Zurek, Encyclopedia Magnetica, CC-BY-4.0
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