A mode S transponder is silent when it is not interrogated. A.

a-mode-s-transponder-is-silent-when-it-is-not-interrogated-a

A mode S transponder is silent when it is not interrogated.

A. True

B. False

I had been asked this question by my school principal while I was bunking the class.

This question is from Modes S System topic in chapter Surveillance Systems, Mapping and Multimode Radars of Avionics

Right option is B. False

Easy explanation: Usually, a transponder remains silent when not interrogated. However, being an integral part of TCAS requires the occasional spontaneous mode S transmissions.