In general, an IR detector will respond to?

A)
Irradiance
B)
RCS
C)
Rotational fluid
D)
Rotational force

Correct Answer :   Irradiance


Explanation : Typically, all it detector will respond to irradiance. Irradiance is area density of the power. Hence, an infrared detector will respond to the density of the radiant power. RCS is measure of radar detection.