Question

Impedance _______. Select one: a. is the opposition to the flow of alternating current b. is the opposition to the flow of direct current c. is rarely used in EEG, since resistance is the measurement of choice in evaluating electrode connectivity. d. is measured in Farads

Answer 1

Impedance is the opposition to the flow of alternating current.

Option a

Explanation:

Electrical impedance is the term used to measure the opposition present when a circuit opposes the flow of an electric current in the presence of voltage. Impedance is measured in the unit of Ohms.

It is often confused with resistance. While resistance is used for ‘direct current’, impedance is used for ‘alternating current’. Impedance includes resistance and reactance both. Just like resistance, presence of impedance prevents extensive damage when there is an electrical surge.