Question

Which of the following statement is false about polarizable electrodes?

(a) they are made using stainless steel

(b) used for recording resting ECG

(c) retain a residual charge when exposed to large pulse of energy

(d) can transmit small bioelectric signals even after getting exposed to large pulse of energy

This question was posed to me in an international level competition.

This intriguing question comes from Recording Electrodes topic in chapter Bioelectric Signal and Electrodes of Biomedical Instrumentation

Answer 1

Right answer is (d) can transmit small bioelectric signals even after getting exposed to large pulse of energy

To explain: Polarizable electrodes usually employ stainless steel and are used for resting ECG or other situations where there is small likelihood that the electrode would be exposed to a large pulse of energy (such as defibrillation discharge) in which case they would retain a residual charge, become polarized, and will no longer transmit the relatively small bioelectric signals, thus become useless.