Signal Classification MCQ Quiz – Objective Question with Answer for Signal Classification

11. What is the period of a signal x(t)?

A. T
B. 2T
C. T/2
D. None of the mentioned

Answer: A

A signal is said to be periodic if the duration of one complete cycle is T and it repeats itself after this duration.

 

12. Which of the given signals are periodic?

A. x(t) = 4 cos(5πt)
B. x(t) = u(t) – 1/2
C. x(t) = 4u(t) + 2sin(3t)
D. x[n] = 2sin(3n)

Answer: A

T=2π / 5π = 2/5, periodic with period 2/5.

 

13. Check whether the signal is periodic or not?
x(t) = cos(4t) + 2sin(8t)

A. Periodic with period π/2
B. Periodic with period 2
C. Periodic with period 2/π
D. Not periodic

Answer: A

T1=2π /4

T2=2π /8

T1/T2 = 2 T

=T1 or 2T2

T=π /2.

The signal x(t) = cos(4t) + 2sin(8t) periodic with period π/2

 

14. Find the periodicity of the following signal. x(t)=cos((2π/7)t)sin((3π/5)t)

A. 30
B. 7
C. 35
D. 5/3

Answer: C

T1=2π/2π/7 = 7,

T2=2π/3π/5=5/3,

T1/T2=5/21,

T=21T1

or

5T2, T=35.

 

15. Find the fundamental period of 1+sin^2 (3π/5)n.

A. 10/3
B. 5
C. 3π/5
D. None of the mentioned

Answer: B

sin2(3π/5)n = (1-cos(6π/5)n)/2

= 1/2-1/2cos(6π/5)n

; period = 6π/(5*2π)

= k/N = 3/5 ; N=5.

 

16. Which signal is called an energy signal?

A. Finite energy and zero power
B. Finite energy and non-zero power
C. Infinite energy and zero power
D. Infinite energy and non-zero power

Answer: A

A signal is said to be an energy signal if it has finite energy and zero average power.

 

17. Which signal is said to be a power signal?

A. Infinite power and zero energy
B. Infinite power and non-zero energy
C. Finite power and infinite energy
D. Finite power and zero energy

Answer: C

A signal is said to be a power signal if it has finite power and infinite energy.

 

18. Determine the periodicity and also find whether it is a power or energy signal?
e(-at)u(t)

A. Periodic and energy signal
B. Non-periodic and energy signal
C. Periodic and power signal
D. Periodic and energy signal

Answer: B

This is non-periodic as it does not repeat itself after any period. And on calculating we will get energy as 1/2a which is finite. Thus it is an energy signal.

 

19. Continuous Impulse signal is a power or energy signal?

A. Power signal
B. Energy signal
C. Both power and energy
D. Neither power nor energy signal

Answer: D

On calculating using the power and energy calculation formula we will arrive at it is neither power nor energy signal.

 

20. Discrete impulse signal is a power or energy signal?

A. Power signal
B. Energy signal
C. Both power and energy signal
D. Neither power nor energy signal

Answer: B

On calculating using the energy formula we will get the energy of this signal as 1 which is a finite value. Thus it is an energy signal.

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