Mcq question 40

Question:

The bus admittance matrix for a power system network is

[tex]\left[ {\begin{array}{*{20}{c}}
{ - j39.9}&{j20}&{j20}\\
{j20}&{ - j39.9}&{j20}\\
{j20}&{j20}&{ - j39.9}
\end{array}} \right][/tex]

There is a transmission line, connected between buses 1 and 3, which is represented by the circuit shown in figure.

If this transmission line is removed from service, what is the modified bus admittance matrix?

problem
A.

[tex]\left[ {\begin{array}{*{20}{c}}
{ - j19.9}&{j20}&0\\
{j20}&{ - j39.9}&{j20}\\
0&{j20}&{ - j19.9}
\end{array}} \right][/tex]

B.

[tex]\left[ {\begin{array}{*{20}{c}}
{ - j39.95}&{j20}&0\\
{j20}&{ - j39.9}&{j20}\\
0&{j20}&{ - j39.95}
\end{array}} \right][/tex]

C.

[tex]\left[ {\begin{array}{*{20}{c}}
{ - j19.95}&{j20}&0\\
{j20}&{ - j39.9}&{j20}\\
0&{j20}&{ - j19.95}
\end{array}} \right][/tex]

D.

[tex]\left[ {\begin{array}{*{20}{c}}
{ - j19.9}&{j20}&{j20}\\
{j20}&{ - j39.9}&{j20}\\
{j20}&{j20}&{ - j19.95}
\end{array}} \right][/tex]

Mcq question 41

Question:

The switch in the figure below was closed for a long time. It is opened at t=0. The current in the inductor of 2H for [tex]t \ge 0[/tex], is

problem
A.

[tex]2.5{e^{ - 4t}}[/tex]
 

B.

[tex]5{e^{ - 4t}}[/tex]
 

C.

[tex]2.5{e^{ - 0.25t}}[/tex]
 

D.

[tex]5{e^{ - 0.25t}}[/tex]

Mcq question 38

Question:

The input voltage VDC of the buck-boost converter shown below varies from 32V to 72V. Assume that all components are ideal, inductor current is continuous, and output voltage is ripple free. The range of duty ratio D of the converter for which the magnitude of the steady-state output voltage remains constant at 48V is

Problem
A.

[tex]\frac{2}{5} \le D \le \frac{3}{5}[/tex]
 

B.

[tex]\frac{2}{3} \le D \le \frac{3}{4}[/tex]
 

C.

[tex]0 \le D \le 1[/tex]
 

D.

[tex]\frac{1}{3} \le D \le \frac{2}{3}[/tex]

Mcq question 37

Question:

The logical gate implemented using the circuit shown below where, V1 and V2 are inputs (with 0V as digital 0 and 5V as digital 1) and Vout is the output, is

Problem
A.

NOT
 

B.

NOR
 

C.

NAND
 

D.

XOR

Mcq question 36

Question:

The output expression for the karnaugh map shown below is

problem
A.

[tex]B\bar D + BCD[/tex]

B.

[tex]B\bar D + AB[/tex]

C.

[tex]\bar BD + ABC[/tex]

D.

[tex]B\bar D + ABC[/tex]

Mcq question 35

Question:

The approximate transfer characteristic for the circuit shown below with an ideal operational amplifier and diode will be

Problem
A.

(A)

B.

(B)

C.

(C)

D.

(D)

Mcq question 34

Question:

The load shown in the figure is supplied by a 400V (line to line), 3-phase source (RYB sequence). The load is balanced and inductive, drawing 3464 VA. When the switch S is in position N, thje three watt-meters W1, W2 and W3 read 577.35 W each. If the switch is moved to position Y, the readings of the watt-meters in watts will be:

 

 

 

 

Problem
A.

W1=1732 and W2=W3=0
 

B.

W1=0, W2=1732 and W3=0

C.

W1=866 and W2=0, W3=866
 

D.

W1=W2=0 and W3=1732

Mcq question 32

Question:

In the system whose signal flow graph is shown in the figure, [tex]{U_1}(s)[/tex] and [tex]{U_2}(S)[/tex] are inputs. The transfer function [tex]\frac{{Y(s)}}{{{U_1}(s)}}[/tex] is

problem
A.

[tex]\frac{{{k_1}}}{{JL{s^2} + JRs + {k_1}{k_2}}}[/tex]
 

B.

[tex]\frac{{{k_1}}}{{JL{s^2} - JRs - {k_1}{k_2}}}[/tex]
 

C.

[tex]\frac{{{k_1} - {U_2}(R + sL)}}{{JL{s^2} + (JR - {U_2}L)s + {k_1}{k_2} - {U_2}R}}[/tex]
 

D.

[tex]\frac{{{k_1} - {U_2}(sL - R)}}{{JL{s^2} - (JR + {U_2}L)s - {k_1}{k_2} + {U_2}R}}[/tex]

Mcq question 31

Question:

Let the signal [tex]x(t) = \sum\limits_{k =  - \infty }^{ + \infty } {{{( - 1)}^k}\delta (t - \frac{k}{{2000}}} )[/tex] be passed through an LTI system with frequency response [tex]H(\omega )[/tex], as given in the figure below. The Fourier series representation of the output is given as

Problem
A.

[tex]4000 + 4000\cos (2000\pi t) + 4000\cos (4000\pi t)[/tex]

B.

[tex]2000 + 2000\cos (2000\pi t) + 2000\cos (4000\pi t)[/tex]
 

C.

[tex]4000\cos (2000\pi t)[/tex]
 

D.

[tex]2000\cos (2000\pi[/tex]

Mcq question 29

Question:

Two passive two-port networks are connected in cascade as shown in figure. A voltage source is connected at port 1.Given

[tex]{V_1} = {A_1}{V_2} + {B_1}{I_2}[/tex]
[tex]{I_1} = {C_1}{V_2} + {D_1}{I_2}[/tex]
[tex]{V_2} = {A_2}{V_3} + {B_2}{I_3}[/tex]
[tex]{I_2} = {C_2}{V_3} + {D_2}{I_3}[/tex]
A1, B1, C1, D1, A2, B2, C2 and D2 are the generalised circuit constants. If the Thevenin equivalent circuit at port3 consists of a voltage source VT and an impedance ZT, connected in series, then

Problem
A.

[tex]{V_T} = \frac{{{V_1}}}{{{A_1}{A_2}}}[/tex], [tex]{Z_T} = \frac{{{A_1}{B_2} + {B_1}{D_2}}}{{{A_1}{A_2} + {B_1}{C_2}}}[/tex]
 

B.

[tex]{V_T} = \frac{{{V_1}}}{{{A_1}{A_2} + {B_1}{C_2}}}[/tex], [tex]{Z_T} = \frac{{{A_1}{B_2} + {B_1}{D_2}}}{{{A_1}{A_2}}}[/tex]
 

C.

[tex]{V_T} = \frac{{{V_1}}}{{{A_1} + {A_2}}}[/tex], [tex]{Z_T} = \frac{{{A_1}{B_2} + {B_1}{D_2}}}{{{A_1} + {A_2}}}[/tex]
 

D.

[tex]{V_T} = \frac{{{V_1}}}{{{A_1}{A_2} + {B_1}{C_2}}}[/tex], [tex]{Z_T} = \frac{{{A_1}{B_2} + {B_1}{D_2}}}{{{A_1}{A_2} + {B_1}{C_2}}}[/tex]