## Introduction to Signals MCQ

Introduction to Signals MCQ, Signals and Systems MCQ, Multiple Choice Questions on Signals, Energy Signal MCQ, Power Signal MCQ, Engineering MCQ, Electronics MCQ,

### Multiple Choice Questions

Q.1. Which of the following signals is/are periodic?

- s(t)=\cos 2t+\cos 3t+\cos 5t
- s(t)=\exp (j8\Pi t)
- s(t)=e^{-7t}\sin 10\Pi t
- s(t)=\cos 2t \cos tu(t)

**Answer: **s(t)=\cos 2t+\cos 3t+\cos 5t & s(t)=\exp (j8\Pi t)

Q.2. Let *δ(t)* denote the delta function. The value of the integral .1.7,6(t)cos —2 dt is

- 1
- -1
- 0
- π/2

**Answer:** 1

Q.3. If a signal *f(t)* has energy *E*, the energy of the signal *f (2t)* is equal to

- E
- E/2
- 2E
- 4E

**Answer: **E

Q.4. The function *x(t)* is shown in the figure. Even and odd parts of a unit-step function *u(t)* are respectively

- \frac{1}{2}, \frac{1}{2}x(t)
- -\frac{1}{2}, \frac{1}{2}x(t)
- \frac{1}{2}, -\frac{1}{2}x(t)
- None of the above

**Answer:** \frac{1}{2}, \frac{1}{2}x(t)

Q.5. The period of the function \cos \frac{\Pi }{4}(t-1) is

- \frac{1}{8}sec
- 8 sec
- 4 sec
- \frac{1}{4}sec

**Answer:** 8 sec

Q.6. A signal x(t)=A\cos (\Omega _{0}t+\phi ) is

- An energy signal
- A power signal
- An energy as well as a power signal
- Neither an energy nor a power signal

**Answer:** A power signal

Q.7. x_{1}(t)=2\sin \Pi t+\cos 4\Pi t and x_{2}(t)=\sin 5\Pi t+3\sin 3\Pi t then

- x1 and x2 both are periodic.
- x1 and x2 both are not periodic.
- x1 is periodic, but x2 is not periodic.
- x1 is not periodic, but x2 is periodic.

**Answer:** x1 and x2 both are periodic.

Q.8. The signal x(t)=2(\cos \Pi t)+3\sin (2t)

- is periodic
- is not periodic
- may or may not be periodic
- none of the above

**Answer:** is not periodic

Q.9. The odd and even components of signal *u(t)* are

- \cos t , \sin t
- \sin t , -\cos t
- \cos t ,j \sin t
- \cos t ,-j \sin t

**Answer:** \cos t ,j \sin t

Q.10. The odd and even components of the sequence

- \left\{ 0.25,0,-0.25\right\},\left\{0.75,1,0.75 \right\}
- \left\{ 1.5,0,-1.5\right\},\left\{1.5,1,1.5 \right\}
- \left\{ 0.25,0,-0.25\right\},\left\{0.5,1,0.5 \right\}
- \left\{ 0.25,0,-0.25\right\},\left\{1.5,1,1.5 \right\}

**Answer:** \left\{ 0.25,0,-0.25\right\},\left\{0.75,1,0.75 \right\}

Q.11. The signal x(t)=e^{-2t}u(t) is

- power signal
- energy signal
- neither power nor energy signal
- either power or energy signal

**Answer:** energy signal

Q.12. The signal x(n)=\cos \frac{2\Pi }{3}nu(n) is

- causal, aperiodic
- causal, periodic
- non causal periodic
- non-causal aperiodic

**Answer:** causal, aperiodic

Q.13. The value of the integral \int_{-\infty }^{\infty }\delta (at-b)=

- \frac{1}{a^{2}}
- \frac{1}{\left| a\right|}
- \frac{1}{a}
- -\frac{1}{a}

**Answer:** \frac{1}{\left| a\right|}

Q.14. The time period of the signal x(t)=\cos 2\Pi t + \sin 5\Pi t is

- 2 sec
- 5 sec
- 10 sec
- 2.5 sec

**Answer:** 2 sec

Q.15. The signal x(n)=\cos 2n is

- periodic with period π
- periodic with period 2π
- periodic with period 4π
- aperiodic

**Answer:** aperiodic

Q.16. Consider the following signals *x(t)* and *y(t )*. The relation between *x(t)* and *y(t)* can be *y(t)*

- x(t+1)
- x(2t+2)
- x(t-1)
- x(2t-1)

**Answer:** x(2t+2)

Q.17. Represent the following signal as the sum of singularity functions

- -r(t)+2r(t)u(t-1)
- r(-t+1)+r(t-1)+2u(t-2)-r(t-2)
- r(-t+1)u(t)+2r(t-1)-r(t-2)-u(t-2)
- r(-t+1)u(t)+r(t-1)-r(t-2)-u(t-2)

**Answer:** r(-t+1)u(t)+2r(t-1)-r(t-2)-u(t-2)

Q.18. The rms value of the signal x(t)=10\cos \left ( 100t+\frac{\Pi }{3} \right )+16\sin \left ( 150t+\frac{\Pi }{3} \right ) is

- \sqrt{160}
- \sqrt{356}
- \sqrt{89}
- \sqrt{178}

**Answer:** \sqrt{178}

Q.19. For the signal *x(t)* shown in the figure which of the following is *x(3t)*

**Answer:**