Final answer:
Increasing the proportional gain Kp in a unity feedback control system with a first-order process will decrease the steady-state error ess to step inputs, but will not affect the time constant of the system. The correct answer is option B.
Step-by-step explanation:
The question pertains to the effect of changing the proportional gain, Kp, on a first-order system described by the transfer function G(s) = K/(Ts+1), where K is the system gain and T is the system time constant, when used within a unity feedback control system. Increasing Kp impacts the system's response to step inputs, particularly in terms of its time constant and steady-state error ess.
When Kp is increased, the overall system gain increases. This does not change the time constant T of the system, which is a property of the system itself. Thus, an increase in Kp does not affect the time constant. However, for a step input, the steady-state error ess is inversely related to the overall system gain. Therefore, increasing Kp will ultimately decrease the steady-state error ess but will not change the time constant.
The correct answer to the question is B. Increasing Kp will decrease the steady-state error ess to step inputs but will not change the time constant of the system.