Laplace Transform

MATLAB

This set of MATLAB Multiple Choice Questions & Answers (MCQs) focuses on “Laplace Transform”.

1. The default Laplace transform, of functions, computed by MATLAB is __________
a) Unilateral
b) Bilateral
c) Multipolar
d) Cannot be computed

2. The laplace transform of step function, u(t), can be calculated by using _____
a) syms t; laplace(t/t)
b) laplace(1)
c) laplace(t/t)
d) sym t; laplace(t/t)

3. How many time domain representations of the following signal is possibly stable?

F(s)=2s+4/(s2+4s+3)…. Where s is the Laplacian frequency

a) 2 for sigma>-1
b) 2 for sigma>-3
c) Only 1 for -3<sigma<-1
d) 1 for sigma<-1

4. The Transfer Function of an L.T.I. system is ___________
a) the impulse response with 0 initial conditions
b) the impulse response with some initial conditions
c) the ramp response with 0 initial conditions
d) the step response with 0 initial conditions

5. What will be the output of the following code?

syms ‘-t’; laplace(4*(-t))

a) Syntactical Error
b) The laplace transform of the time reversed ramp function.
c) -4/s2
d) Logical Error

6. What is the output of the following code?

(z,p)=tf2zp([1],[1,0])

a) Error
b) z=0,p=0
c) z=0,p=1
d) z=1,p=0

7. The final value theorem is applicable if __________
a) Poles lie on right half of s plane
b) Poles lie on left half of s plane
c) Poles lie on the imaginary axis
d) Zeros lie on left half of s plane

8. What is the output of the following code?

laplace[‘t^t’]

a) A gamma function
b) Error due to []
c) Error due to ‘’
d) Cannot be determined

9. If f(t)=f1(t)+f2(t), the laplace transform of f(t) exists if f1(t) and f2(t) does not have the same R.O.C.
a) True
b) False

10. What is the output of the following code?

[r,p,k]=residu(z,p);….. Assuming z and p are vectors of unequal length

a) Returns the transfer function as partial fractions
b) Returns the transfer function variable
c) Returns an error
d) Cannot be determined

11. What is the output of the following code?

(r,p,k)=residue(z,p);….. Assuming z and p are vectors of unequal length

a) Returns the residue and poles for the partial fractions
b) Returns the zeros and poles
c) Returns a syntactical error
d) Cannot be determined

12. What is the default variable used to represent the laplace transform in the output?
a) s
b) z
c) S
d) p

13. A causal system is stable if the pole lies on the right half of the s-plane.
a) True
b) False

14. The laplace transform of the following function.

f(t)= 3 when t=[0-5] 
     =  0 otherwise is….. L denotes Laplace Transform

a) L{3u(t+3)-3u(t-5)}
b) L{3u[t+5]-u[t-5]}
c) L(3u(t)-3u(t-5))
d) L(u[t]-3u[t+5])

15. What will be the output of the following code?

ilaplace(‘1/s’)

a) Error
b) 1
c) u(t)
d) 0

16. An L.T.I. system is stable if _______
a) Poles lie on left half of s-plane
b) The R.O.C. encompasses the imaginary axis
c) The poles lie on the left half of s-plane and the R.O.C. encompasses the imaginary axis
d) Cannot be determined

17. The final value of the following transfer function is ________

F(s)= 2/s(s-824)

a) Not calculable
b) -1/412
c) 0
d) 1

18. The number of inverse lapalace transform of a function is equal to ________
a) the number of poles
b) the number of poles+1
c) the number of poles-1
d) cannot be determined

19. The laplace transform method used to solve a differential function is ____ than the classical way.
a) Easier
b) Harder
c) Moderately difficult
d) Relatively difficult

20. What is the output of the following code?

laplace[t,t,2]

a) 1/16
b) Error
c) 1/s^2
d) Cannot be determined

21. The laplace transform of a cascaded system is defined if _______
a) the individual systems have a common R.O.C.
b) the individual systems doesn’t have a common R.O.C.
c) the impulse response of each system is defined
d) cannot be determined

22. The inverse laplace transform of a function in s-domain is the transfer function of the system.
a) True
b) False

23. The following output is defined for _______

>>ilaplace(1/s)
>> ans=
        1

a) t>0
b) t>=0
c) for all t
d) t<0

24. The differential equation d2p/dt2=9t has a solution.
a) 3/(2*t3)
b) cannot be determined
c) no solution
d) ilaplace(9/s4)

25. What is the output of the following code?

syms t; laplace(-t/t)

a) The laplace transform of u(-t)
b) The laplace transform of -u(t)
c) The laplace transform of -u(-t)
d) The laplace transform of -u(t)

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