as the unit for impedance 
. Is it legitimate to use it?
in an 
circuit come from. Why
is
?
or greater than 
at 
?
. But then 
is arbitrarily large, and in an 
circuit we should have zero voltage across the resistor. But in an circuit the voltage across the resistor is nonzero for some time. Why is there a disagreement?
mean physically?
approximation for come from?
, why does the term
become
?
for other circuits?
and 
construction is a voltage divider?