What is the system's reaction to an instantaneous burst of energy called?

• A. Impulse Response
• B. Step Response
• C. Frequency Response
• D. Transfer Function

Answer: (A)

An instantaneous burst of energy is modeled as a Dirac delta input, and the system’s reaction to that input is called the impulse response. This response is fundamental for linear time-invariant systems because any input can be built up from impulses, and the output is obtained by convolving the input with the impulse response. In other words, h(t) tells you exactly how the system responds over time to a single, instantaneous spike of energy. The step response, by contrast, comes from a gradual, finite input step; the frequency response describes how the system behaves across different frequencies; the transfer function is the Laplace-domain representation of the same impulse-response relationship.