Question

Step signal is the signal whose values is :

(a) 1 for all values greater than zero

(b) Indeterminate at zero

(c) It is zero for time less than zero

(d) All of the mentioned

This question was addressed to me in a national level competition.

Origin of the question is Standard Test Signals in section Time Response Analysis, Design Specifications and Performance Indices of Control Systems

Answer 1

The correct choice is (d) All of the mentioned

For explanation I would say: Step signal is the signal whose value varies from zero to level in zero time.