Typical root locus diagram of a system is shown below. Find the point where the system is critically damped. [Figure description: A root locus plot on the Re-Im plane. There are open-loop poles (x marks) on the negative real axis: one at far left point A, one at an intermediate location, and one near the origin on the right. A zero (dot) lies on the real axis between the leftmost pole and the next pole. A real-axis segment runs from A toward the right to a breakaway point B located just left of the imaginary axis, where the locus leaves the real axis and splits into two complex branches that curve upward (through point C) and downward (through point D), both crossing/approaching the imaginary axis near the top and bottom. Points C and D are on the imaginary axis (upper and lower), B is the breakaway point on the real axis near the origin, and A is the leftmost pole on the real axis.]
- A. At Point 'A'
- B. At Point 'B'
- C. At Points 'C' and 'D'
- D. None of the above
Answer: B. At Point 'B'
Explanation: Critical damping corresponds to repeated real roots, which occurs at the breakaway point B on the real axis.