What is the primary function of a feedback control system?
Answer: A
Feedback control systems work by comparing the desired output with actual output and reducing the error between them through corrective action.
Q.2Easy
The transfer function of a system is defined as the ratio of:
Answer: B
Transfer function G(s) = Y(s)/U(s) is the ratio of Laplace transforms of output to input assuming zero initial conditions.
Q.3Easy
Which of the following represents a first-order system?
Answer: B
A first-order system has only s¹ as the highest power in the denominator. G(s) = K/(τs + 1) is the standard first-order form.
Q.4Easy
The characteristic equation of a system is s² + 4s + 3 = 0. The system is:
Answer: C
Roots are s = -1 and s = -3 (both negative). All poles are in the left half-plane, making the system stable.
Q.5Easy
In a bode plot, the magnitude is plotted on a scale of:
Answer: B
Bode plots use dB (20log₁₀|G(jω)|) for magnitude on a logarithmic scale and phase in degrees on a semi-log plot.
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Q.6Easy
For a system G(s) = 1/(s(s+2)), the number of poles at origin is:
Answer: B
The system has one pole at s=0, making it Type 1. The denominator has s¹ factor representing one integration.
Q.7Easy
The settling time of a control system is defined as the time taken to:
Answer: C
Settling time is the time required for the transient to decay and response to remain within 2% (or 5%) of the steady-state value.
Q.8Easy
Which of the following is NOT a characteristic of a proportional (P) controller?
Answer: B
A proportional controller cannot eliminate steady-state error completely for step inputs in type-0 systems. An integral term is needed for zero steady-state error.
Q.9Easy
For a unity feedback system with G(s) = K/(s(s+3)(s+5)), what is the system type?
Answer: B
The system type equals the number of poles at origin. Here, there is one pole at origin (s in denominator), making it Type 1.
Q.10Easy
A second-order system has damping ratio ζ = 0.5. What is the nature of its response?
Answer: B
For ζ < 1, the system is underdamped and exhibits oscillatory response. At ζ = 0.5, there are definitely oscillations with exponential decay.
Q.11Easy
In root locus analysis, as the gain K increases from 0 to ∞, the closed-loop poles move along specific paths. Where do these paths originate?
Answer: B
The root locus starts at open-loop poles (K=0) and ends at open-loop zeros (K=∞). This is a fundamental property of root locus construction.
Q.12Easy
For the open-loop transfer function G(s)H(s) = K(s+1)/((s+2)(s+3)(s+4)), the system order is:
Answer: B
System order is determined by the highest power of 's' in the characteristic equation denominator. Here, it's (s+2)(s+3)(s+4) = s³+..., so order is 3.
Q.13Easy
In a state-space representation, if the system has 4 state variables, what is the dimension of the state vector?
Answer: C
The state vector x(t) contains all state variables. With 4 state variables, it's a 4×1 column vector, so the dimension is 4.
Q.14Easy
Which of the following transfer functions represents a Type-2 system?
Answer: A
Type of system is determined by the number of poles at origin. Option A has s² in denominator, making it Type-2
Q.15Easy
In the root locus of a system with open-loop transfer function G(s)H(s) = K(s+2)/(s(s+1)(s+3)), how many branches exist?
Answer: B
Number of root locus branches = max(number of poles, number of zeros) = max(3, 1) = 3
Q.16Easy
What is the bandwidth of a first-order system with time constant τ = 0.1 seconds?
