that relates the magnitude of the induced voltage in one coil to the rate of change of current, 
in the other coil, through the equation
of: a pair of coils (or circuits), or of a transformer,
is: the quantity that relates the magnitude of the induced voltage in one coil to the rate of change of current, in the other coil, through the equation
[P4.4]
has as its SI unit: the henry (H), where 
[P4.4]
often is abbreviated: to mutual inductance. [P4.4]
See also 'mutual induction'.
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