#### 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?

[tex]\left[ {\begin{array}{*{20}{c}}

{ - j19.9}&{j20}&0\\

{j20}&{ - j39.9}&{j20}\\

0&{j20}&{ - j19.9}

\end{array}} \right][/tex]

[tex]\left[ {\begin{array}{*{20}{c}}

{ - j39.95}&{j20}&0\\

{j20}&{ - j39.9}&{j20}\\

0&{j20}&{ - j39.95}

\end{array}} \right][/tex]

[tex]\left[ {\begin{array}{*{20}{c}}

{ - j19.95}&{j20}&0\\

{j20}&{ - j39.9}&{j20}\\

0&{j20}&{ - j19.95}

\end{array}} \right][/tex]

[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

[tex]2.5{e^{ - 4t}}[/tex]

[tex]5{e^{ - 4t}}[/tex]

[tex]2.5{e^{ - 0.25t}}[/tex]

[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

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

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

[tex]0 \le D \le 1[/tex]

[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, V_{1} and V_{2} are inputs (with 0V as digital 0 and 5V as digital 1) and V_{out} is the output, is

NOT

NOR

NAND

XOR

#### Mcq question 36

**Question: **

The output expression for the karnaugh map shown below is

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

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

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

[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

(A)

(B)

(C)

(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 W_{1}, W_{2} and W_{3} read 577.35 W each. If the switch is moved to position Y, the readings of the watt-meters in watts will be:

W_{1}=1732 and W_{2}=W_{3}=0

W_{1}=0, W_{2}=1732 and W_{3}=0

W_{1}=866 and W_{2}=0, W_{3}=866

W_{1}=W_{2}=0 and W_{3}=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

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

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

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

[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

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

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

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

[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]

A_{1}, B_{1}, C_{1}, D_{1}, A_{2}, B_{2}, C_{2} and D_{2} are the generalised circuit constants. If the Thevenin equivalent circuit at port3 consists of a voltage source V_{T} and an impedance Z_{T}, connected in series, then

[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]

[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]

[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]

[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]