These **MCQs** are very fruitful for the preparation of the **University exams, Engineering exams,** and various **competitive exams**.

This MCQs are based on the following topics:

i. O**pen-loop and closed-loop control system**

**ii. Modelling of Mechanical system.**

**iii. Feedback of the control system and its effect.**

** CONTROL SYSTEM – BASICS OF CONTROL SYSTEM MCQs**

1. A control system whose control action is somehow dependent on the output is referred as:

Explanation:- In open-loop control system control action is not dependent on the output whereas in closed-loop control system control action is dependent on the output.

2. In an open-loop control system

Explanation:- In open-loop control system control action is not dependent on the output whereas in closed-loop control system control action is dependent on the output.

3. Which one of these is an example of a closed-loop system:

Explanation:- In closed-loop control system control action is dependent on output. A human being is also considered as an example of a close-loop control system because they keep on taking action to get the desired output.

4. Due to negative feedback the overall gain of the system:

Explanation:- Negative feedback system has one disadvantage that it reduces the gain of the system while positive feedback increases the gain of the system.

5. Open-loop systems are generally more stable than closed-loop systems.

Explanation:-Open-loop systems are more stable in comparison to close loop systems because open-loop system output is not dependent on feedback input, so output remains constant (stable) even after the disturbances.

6. By using the force-voltage analogy method, the Mass(M) of the Mechanical translational system is equivalent to which element of the electrical system:

Explanation:- In force-voltage analogy method, Force(F)= Voltage (V); Mass(M)=Inductance(L); Damping coefficient(D)=Resistance(R); Spring stiffness(K)=Reciprocal of capacitance(1/C); Dispalacement(x)=Charge(q); Velocity(v)=current(i).

7. The ratio of the Laplace Transform of the output and input keeping all the initial condition zero is known as:

Explanation:- Transfer function T(s) is the ratio of the Laplace Transform of output variable C(s) to the Laplace transform of the input variable R(s) assuming all initial condition zero i.e T(s)=C(s)/R(s).

8. By using the torque-current analogy method, the Torsional spring stiffness(K) of the Mechanical Rotational system is equivalent to which element of the electrical system:

Explanation:-torque-current analogy method, Torque(T)=current(i); moment of inertia(J)= Capacitance(C); Damping coefficient(D)=Reciprocal of Resistance (1/R); Torsional spring stiffness (K)= reciprocal of Inductance (1/L) ; Angular displacement(θ)=Magnetic flux linkage(Φ) ; angular velocity(w)= Violtage(V) .

9. D’Alembert Principle states that the product of externally applied forces and the forces resisting motion in any given direction is zero.

Explanation:- D’Alembert Principle states that the sum of externally applied forces and the forces resisting motion in any given direction is zero.

10. Transfer function of a differential circuit shown below is:

Explanation:- Transfer function is obtained by taking the ratio of Laplace transform of Output voltage to Laplace transform of input Voltage. In the given figure, Vi(s)= (R+1/sC)I(s) and Vo(s)= RI(s) then, Transfer fuction T(s) = Vo(s)/Vi(s)= RI(s)/(R+1/sC)I(s) so by solving this we get T(s)= SRC/(1+SRC).

11. The transfer functions are defined only for which type of system :

Explanation:- Transfer function is only defined for Linear and Time-Invariant systems i.e linear time-invariant(LTI) systems.

12. Which among the following is useful in writing the equation of motion of the mechanical system.

Explanation:- D’Alembert Principle states that”For anybody, the algebraic sum of externally applied forces and the forces resisting motion in any given direction is zero”.This principle is used to write the mathematical equations of motion of mechanical systems.

13. Which among the following is not the disadvantage of closed control system :

Explanation:-In open-loop control system optimization is not possible but in close loop control system optimization is possible.

14. The system in which the motion of the body is about its own axis is known as the Translational system.

Explanation:-

**Translational systems**-The system in which the motion of the body is along a straight line or a curved path is known as the Translational system.

**Rotational Systems**– The system in which the motion of the body is about its own axis is known as the Rotational system.

15. Which of the following is the element of rotational motion of the Mechanical system:

Explanation:- The elements of rotational motion of the Mechanical system are: Inertia(J), Damper(D), Spring(K).

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