GATE ECE 2017 Set 1 | Question: 49

Question

The Nyquist plot of the transfer function

$$G(s)=\frac{K}{(s^{2}+2s+2)(s+2)}$$

does not encircle the point $(-1+j0)$ for $K=10$ but does encircle the point $(-1+j0)$ for $K=100$. Then the closed loop system (having unity gain feedback) is 

• A. stable for $K=10$ and stable for $K=100$
• B. stable for $K=10$ and unstable for $K=100$
• C. unstable for $K=10$ and stable for $K=100$
• D. stable for $K=10$ and unstable for $K=100$