IIR is infinite impulse response. FIR is finite impulse response.

impulse response is exponential increasing with respect to time.

The short pathway that carries the impulse for an automatic response is called a reflex arc.

The impulse response of an R-L circuit is an exponentially decaying signal. It represents the behavior of the circuit when subjected to a Dirac delta function input or an impulse signal. The response decays over time due to the inductor's energy storage capability.

We can divide filters two types based on the length of the impulse resopnse 1. FIR where the impulse responce is finite 2. IIR where the impulse response is infinite