QUIZ 2 MEC522 OCT2022/23

First order system is defined as : ______ [CO1/PO1]

• Number of poles at origin

• Order of the differential equation

• Total number of poles of equation

• Total number of poles and order of equation

Answer explanation

First order system is defined by total number of poles and also which is same as the order of differential equation.

Laplace transform of unit impulse signal is :

[CO1/PO1]

• A/s

• A

• 1

• 1/s

Answer explanation

Laplace response of impulse signal is one which implies Laplace response is systems response.

• Over damped

• Critically damped

• Undamped

• Underdamped

Answer explanation

The given equation is: s^2 + 2s + 2 = 0

It is a second-order differential equation.

The Laplace transform of a standard form of a second-order differential equation is:

Thus, the system is underdamped.

The impulse response of an RL circuit is:

[CO1/PO1]

• Parabolic function

• Step function

• Rising exponential function

• Decaying exponential function

Answer explanation

The RL circuit comprises of the resistor and inductor connected in series.

The equation can be written as:

1 = RI(s) + sLI(s)

1 = I(s) [R + sL]

I(s) = 1 / (R +sL)

Taking the inverse Laplace, we get:

The equation clearly depicts that the impulse response is a decaying exponential function.

• zero

• infinity

• 1/14

• 14

The steady-state error due to a unit step into a type 1 system is: ____ [CO1/PO1]

• zero

• infinity

The damping ratio and peak overshoot are measures of: [CO1/PO1]

• Relative stability

• Speed of response

• Steady state error

• Absolute stability

Answer explanation

Speed of response is the speed at which the response takes the final value and this is determined by damping factor which reduces the oscillations and peak overshoot as the peak is less then the speed of response will be more.

The maximum overshoot is: [CO1/PO1]

• To measure the relative stability

• A system with large overshoot is desirable

• It occurs at second overshoot

• Both b and c

Answer explanation

To measure the relative stability ,the maximum overshoot is used. It is given a time domain specification and the system is desirable with small overshoot and it occurs at first overshoot.

Consider the following statement regarding Routh Hurwitz criterion: [CO1/PO1]

• It gives absolute stability

• It gives gain and phase margin

• It gives the number of roots lying in RHS of the s-plane

• It gives gain, phase margin and number of roots lying in RHS of the s-plane

Answer explanation

Routh Hurwitz gives the gain, phase margin, absolute stability and roots on the right of the s-plane.

Which of the test signals are best utilized by the stability analysis. [CO1/PO1]

• Impulse

• Step

• Ramp

• Parabolic

Answer explanation

The Impulse test signals are best utilised by the stability analysis because the computational task is reduced to much extent.