The way in which the water pH of a swimming pool is controlled can be thought of as an analogy for a control system in an organism.The pool owner tests the pH of the water using litmus paper and compares that result against a predetermined value.If the pool's pH is,for example,1.5 units below the accepted level,the owner corrects the pH by adding a substance such as sodium carbonate.In this analogy,the pH represents
A) the controlled variable.
B) negative feedback.
C) positive feedback.
D) feed-forward information.
E) the set point.

Question

Quizplus · Accepted Answer

The pH of the water in the swimming pool represents the controlled variable, which is being monitored and adjusted to maintain a desired level. The owner's actions (adding sodium carbonate) represent the corrective measures taken when the controlled variable is outside of the accepted level.

The Way in Which the Water PH of a Swimming