Q.1

An ac circuit has an impedance of (3 + johm for fundamental. The impedance for fifth harmonic is

  • (15 + j 30) Ω
  • (15 + j 6) Ω
  • (3 + j 30) Ω
  • (3 + j 1.2) Ω
Q.2

The integral of unit step function is a ramp of slope unity.

  • True
  • False
Q.3

Which one of the systems described by the following I/P - O/P relations is time invariant

  • y(n) = n x(n)
  • y(n) = x(n) - x(n - 1)
  • y(n) = x(- n)
  • y(n) = x(n) cos 2pf0n
Q.4

Two rectangular waveforms of duration t1 and t2 seconds are convolved. What is the shape of the resulting waveform?

  • Triangular
  • Rectangular
  • Trapezoidal
  • Semi-circular
Q.5

FIR digital filter having __________ stability than FIR filter.

  • good stability
  • poor stability
  • stability not guarnteed
  • poor stability
Q.6

Fourier transform of non periodic DT signal is

  • aperiodic
  • Periodic
  • both a and b
  • None of these
Q.7

The derivative of unit step function is

  • unit impulse
  • ramp with slope 1
  • impulse
  • either (a) or (b)
Q.8

The coefficients Fn in the exponential form of Fourier series are

  • independent of frequency
  • functions of frequency
  • even function of frequency
  • odd functions of frequency
Q.9

If I (s) , initial value of i(t) is

  • 5A
  • 12.5 A
  • 0.05 A
  • 1250 A
Q.10

L[c1f1(t) + c2f2(t)] =

  • c1 F1 (jω) + c2 F2(jω)
  • c1 F1 (jω) - c2 F2(jω)
  • c1 F1 (jω) + c2 F2(jω) + c1c2
  • c1 F1 (jω) + c2 F2(jω) + c1/c2
Q.11

Pick the odd one

  • variance
  • standard deviation
  • expectation
  • chebyshev inequality
Q.12

A unit step function is used to represent the closing a switch in a constant voltage system.

  • True
  • False
Q.13

State variable formulation is very suitable for computer solution.

  • True
  • False
Q.14

Inverse Fourier transform of 'is

  • U(t)
  • δ(t)
  • '0'
  • infinite
Q.15

For a wave v = V 1m sin (ωt + θ1 ) - V3m sin (3ωt + θ3), the rms value is (0.5 V21m + 0.5 V23m)0.5

  • True
  • False
Q.16

The function Ae(s + jω)t represens a rotating phasor having a magnitude increasing with time.

  • True
  • False
Q.17

Half wave sysmmetry means f(t) = - f(t ± T/2).

  • True
  • False
Q.18

If X(z) = 2az-1/(1 - az-1)3 and |a| < |z|, then the initial value x0 is

  • 0
  • 1
  • 2
Q.19

In an ac circuit the fundamental component of current wave lags the corresponding voltage wave by 20°. The third harmonic component of current wave lags the corresponding voltage by an angle.

  • less than 20°
  • more than 20°
  • equal to 20°
  • equal to or more than 20°
Q.20

If I (s) , initial value of i(t) is

  • 5A
  • 12.5 A
  • 0.05 A
  • 1250 A
Q.21

Which of following is recursive system?

  • y(n - 1)
  • y(n + 1)
  • y(n)
  • y(n) + y(n + 1)
Q.22

A voltage v(t) which is a gaussian ergodic random process witha mean of zero and a varance of 4 volt2 is measured by a meter which first square and then reads its dc component. The reading will be

  • 0
  • 4
  • 16
  • 2
Q.23

The Fourier transform of f(t) = cos ω0t is

  • p[δω0 + δ(- ω0)]
  • p[δ(ω - ω0) + δ(ω + ω0)]
  • p[δω0 - δ(- ω0)]
  • p[δ(ω - ω0) - δ(ω + ω0)]
Q.24

A voltage v =sin ωt +sin 5 ωt is applied to a pure capacitor having capacitance of 1 μF. If ω =rad/sec, the current through the capacitor is

  • 0.0314 cos 314 t + 0.0157 cos 1570 t
  • 0.0314 sin 314 t + 0.0157 sin 1570 t
  • 0.0314 cos 314 t + 0.0314 cos 1570 t
  • 0.0157 cos 314 t + 0.0157 cos 1570 t
Q.25

Pick out the odd one

  • stochastic variable
  • stochastic function
  • random variable
  • random experiment
Q.26

X and Y are two random variables and Z = X + Y . Letmz, mz, mx, my represent mean of Z, X and Y. Then

  • mz = mx + my
  • mzmx + my
  • mz< mx + my
  • mz > mx + my
Q.27

F.T. of continuous non-periodic signal is

  • periodic
  • aperiodic
  • a and b
  • none
Q.28

The function Ae(s + jω)t represens a rotating phasor having a magnitude increasing with time.

  • True
  • False
Q.29

If I (s) , initial value of i(t) is

  • 5A
  • 12.5 A
  • 0.05 A
  • 1250 A
Q.30

If ξ f(t) = F(jω), ξf(t-a) =

  • F(jω) e-jωa
    07-75-3.png
  • F(jω) ejωa
    07-75-3.png
  • a F(jω) ejωa
Q.31

The function Ae(s + jω)t represens a rotating phasor having a magnitude increasing with time.

  • True
  • False
Q.32

A voltage v(t) which is a gaussian ergodic random process witha mean of zero and a varance of 4 volt2 is measured by a meter which first square and then reads its dc component. The reading will be

  • 0
  • 4
  • 16
  • 2
Q.33

If I (s) , initial value of i(t) is

  • 5A
  • 12.5 A
  • 0.05 A
  • 1250 A
Q.34

L[c1f1(t) + c2f2(t)] =

  • c1 F1 (jω) + c2 F2(jω)
  • c1 F1 (jω) - c2 F2(jω)
  • c1 F1 (jω) + c2 F2(jω) + c1c2
  • c1 F1 (jω) + c2 F2(jω) + c1/c2
Q.35

The sampling of a function f(l) = sin 2pf0t starts from a zero crossing. The signal can be detected if sampling time T is

Q.36

X and Y are two random variables and Z = X + Y . Letmz, mz, mx, my represent mean of Z, X and Y. Then

  • mz = mx + my
  • mzmx + my
  • mz< mx + my
  • mz > mx + my
Q.37

F.T. of continuous non-periodic signal is

  • aperiodic
  • periodic
  • a and b
  • none
Q.38

Which of following is recursive system?

  • y(n - 1)
  • y(n + 1)
  • y(n)
  • y(n) + y(n + 1)
Q.39

If X(z) = 2az-1/(1 - az-1)3 and |a| < |z|, then the initial value x0 is

  • 0
  • 1
  • 2
Q.40

The function shown in the figure

  • impulse function
  • signum function
  • unit step function
  • none of the above
Q.41

If f1(t) ↔ F1 (jω) and f2(t) ↔ F2(jω), then f1(t)↔ f2(t)

  • F1(jω) F2(jω)
    14-188-3.png
  • F1(jω)*F2(jω)
    14-188-3.png
  • none of these
Q.42

X and Y are two random variables and Z = X + Y . Letmz, mz, mx, my represent mean of Z, X and Y. Then

  • mz = mx + my
  • mzmx + my
  • mz< mx + my
  • mz > mx + my
Q.43

F.T. of continuous non-periodic signal is

  • aperiodic
  • periodic
  • a and b
  • none
Q.44

In an ac circuit the fundamental component of current wave lags the corresponding voltage wave by 20°. The third harmonic component of current wave lags the corresponding voltage by an angle.

  • less than 20°
  • more than 20°
  • equal to 20°
  • equal to or more than 20°
Q.45

Parseval's theorem for energy tells that

  • Not defined for energy
Q.46

Parseval's theorem for energy tells that

  • Not defined for energy
Q.47

The final value of is

  • 2
  • 1
  • zero
Q.48

L[c1f1(t) + c2f2(t)] =

  • c1 F1 (jω) + c2 F2(jω)
  • c1 F1 (jω) - c2 F2(jω)
  • c1 F1 (jω) + c2 F2(jω) + c1c2
  • c1 F1 (jω) + c2 F2(jω) + c1/c2
Q.49

F.T. of continuous non-periodic signal is

  • aperiodic
  • periodic
  • a and b
  • none
Q.50

A wave f(t) has half wave symmetry and time period equal to T. Then

0 h : 0 m : 1 s