Question

Define capacitive reactance. Give its units.

Answer 1

The peak value of current I is given by I_m = `"v"_"m"/(1//"c"_omega)`. Let us compare this equation with I_m = `"V"_"m"/"R"` from resistive circuit. The quantity `1/(omega"C")` plays the same role as the resistance R in resistive circuit. This is the resistance offered by the capacitor, called capacitive reactance (X_C). It measured in ohm.
X_C = `1/(omega"C")`.