# Networks Signals and Systems | Subject Wise

## Networks Signals and Systems Subject Wise

 Question 1
Consider the two-port resistive network shown in the figure. When an excitation of 5 V is applied across Port 1, and Port 2 is shorted, the current through the short circuit at Port 2 is measured to be 1 A (see (a) in the figure).
Now, if an excitation of 5 V is applied across Port 2, and Port 1 is shorted (see (b) in the figure), what is the current through the short circuit at Port 1?
 A 0.5 A B 1 A C 2 A D 2.5 A
Question 1 Explanation:
 Question 2
The RC circuit shown below has a variable resistance R(t) given by the following expression :

for 0 ≤ t < T

where R0 = 1 Ω, and C = 1 F. We are also given that T = 3 R0C and the source voltage is Vs = 1 V. If the current at time
t = 0 is 1 A, then the current I(t), in amperes, at time t = T/2 is __________ (rounded off to 2 decimal places).

 A Fill in the Blank Type Question
Question 2 Explanation:
 Question 3
In the circuit shown, if v(t) = 2 sin (1000 t) volts, R = 1 kΩ and C = 1 μF, then the steady-state current i(t), in milliamperes (mA), is

 A Sin(1000 t) + cos(1000 t) B 2 sin(1000 t) + 2 cos(1000 t) C 3 sin(1000 t) + cos(1000 t) D Sin(1000 t) + 3 cos(1000 t)
Question 3 Explanation:
 Question 4
The figure shows an RLC circuit exited by the sinusoidal voltage 100 cos (3t) volts, where t is in seconds.
The ratio is ______
 A Fill in the Blank Type Question
Question 4 Explanation:
V1=
V1=
V2=
=
 Question 5
In the circuit shown, the voltage VIN(t) is described by:

where t is in seconds. The time (in seconds) at which the current I in the circuit will reach the value 2 Amperes is _______.
 A Fill in the Blank Type Question
Question 5 Explanation:
 Question 6
The matrix for a two-port network is defined by:

The parameter for the given two-port network (in ohms, correct to two decimal places) is ____________.

 A Fill in the Blank Type Question
Question 6 Explanation:
 Question 7
For the circuit given in the figure, the magnitude of the loop current (in amperes, correct to three decimal places) 0.5 second after closing the switch is __________.(upto 3 decimal places)

 A Fill in the Blank Type Question
Question 7 Explanation:
The circuit given here has no initial conditions as no energy is stored in inductor prior to switching.
 Question 8
For the circuit given in the figure, the magnitude of the loop current (in amperes, correct to three decimal places) 0.5 second after closing the switch is __________.(upto 3 decimal places)

 A Fill in the Blank Type Question
Question 8 Explanation:
The circuit given here has no initial conditions as no energy is stored in inductor prior to switching.
 Question 9
For the circuit given in the figure, the magnitude of the loop current (in amperes, correct to three decimal places) 0.5 second after closing the switch is __________.(upto 3 decimal places)

 A Fill in the Blank Type Question
Question 9 Explanation:
The circuit given here has no initial conditions as no energy is stored in inductor prior to switching.
 Question 10
Consider the network shown below with and The network is connected to a constant voltage source of 11 V.

The magnitude of the current (in amperes, accurate to two decimal places) through the source is ____________.
 A Fill in the Blank Type Question
Question 10 Explanation:

Total resistance RT is resultant of following combination,
We have values for R1 and R3,
and
So,  Thus, current through 11 V voltage source is,
 Question 11
For the circuit given in the figure, the voltage (in volts) across the capacitor is
 A B C D
Question 11 Explanation:
 Question 12
In the circuit shown, V is a sinusoidal voltage source. The current I is in phase with voltage V.
 A Fill in the Blank Type Question
Question 12 Explanation:
 Question 13
The output V0 of the diode circuit shown in the figure is connected to an averaging DC voltmeter. The reading on the DC voltmeter in Volts, neglecting the voltage drop across the diode, is ______.
 A Fill in the Blank Type Question
Question 13 Explanation:
->Below circuit is a half wave rectifier and DC voltmeter will read the average value of V0
->Hence average value of V0 i.e. output of half wave rectifier is given by, Answer Range ( 3.15 to 3.21 )
 Question 14
The switch in the circuit, shown in the figure, was open for a long time and is closed at t = 0.
The current i(t) (in ampere) at t = 0.5 seconds is ________
 A Fill in the Blank Type Question
Question 14 Explanation:
 Question 15
Consider a two-port network with the transmission matrix: If the network is reciprocal, then
 A T-1 =T B T2 =T C Determinant (T) = 0 D Determinant (T) = 1
Question 15 Explanation:
A two port network is reciprocal in transmission parameters
if AD – BC = 1 i.e. Determinant(T) = 1

Note : If network is reciprocal, then Determinant (T) = 1
 Question 16
A network consisting of a finite number of linear resistor (R), inductor (L), and capacitor C. elements, connected all in series or all in parallel, is excited with a source of the form The source has nonzero impedance. Which one of the following is a possible form of the output measured across a resistor in the network?
 A B C D
Question 16 Explanation:
The property of any LTI system or network is if the excitation contains 'n' number of different frequency then the response also contains exactly n number of different frequency term and the output frequency and input frequency must be same however depending on components there is a possible change in amplitude and phase but never the frequency.
If the source has 3 frequency terms as given

then any voltage or any current of any element should have also 3 terms based on this option B. and D. are eliminated.
If we take option C.. It has 3 frequency term but it also suggest there is a phase change so 4„ but amplitude must be same as input as ak is present which may not be true always.
So option A. is correct, as it suggest frequency term of output and inputs are same with possible change in amplitude and phase, because we have ().
 Question 17
In the circuit shown, at resonance, the amplitude of the sinusoidal voltage (in Volts) across the capacitor is ________.
 A Fill in the Blank Type Question
Question 17 Explanation:
At resonance

VC=I*XC=25V
Amplitude of 25 Volt VC = 25 Volt
Hence, the correct answer is 25
 Question 18
In the given circuit, the values of V1 and V2 respectively are:
 A 5 V, 25 V B 10 V, 30 V C 15 V. 35 V D 0 V, 20 V
Question 18 Explanation:

Current flowing through both the parallel 4 Ω will be I.
So, by KVL
by KVL

V1 = 5 volts
V2 =25 volts
 Question 19
In the given circuit, the maximum power (in Watts) that can be transferred to the load RL is ________.
 A Fill in the Blank Type Question
Question 19 Explanation:
 Question 20
In the circuit shown below, Vs is a constant voltage source and IL is a constant current load.

The value of IL that maximizes the power absorbed by the constant current load is
 A B C D
Question 20 Explanation:
Under maximum power transfer condition, half of Vth is droped across Rth and remaining Vth / 2 droped across load.
So we can say under MPT Vs / 2 will appear on the load
so
 Question 21
The switch has been in position 1 for a long time and abruptly changes to position 2 at t= 0.

If time t is in seconds, the capacitor voltage Vc (in volts) for t>0 is given by
 A 4(1 —exp (—t/0.5)) B 10 — 6 exp (—t/0.5) C 4(1 — exp (-0.6)) D 10 — 6 exp (—t/0.6)
Question 21 Explanation:

 Question 22
The figure shows an RLC circuit with a sinusoidal current source. At resonance, the ratio|IL|/|IR|, i.e., the ratio of the magnitudes of the inductor current phasor and the resistor current phasor, is___
 A Fill in the Blank Type Question
Question 22 Explanation:
At resonance (for parallel RLC circuit)
IR = I
IL = QI < – 90°
IC = QI < 90°
For parallel RLC circuit
 Question 23
The z-parameter matrix for the two-port network shown is ,
Where the entries are in    Suppose

Then the value of (in) equals to
 A Fill in the Blank Type Question
Question 23 Explanation:
 Question 24
In the given circuit, each resistor has a value equal to What is the equivalent resistance across the terminals a and b?
 A B C D
Question 24 Explanation:
 Question 25
In the circuit shown in the figure, the magnitude of the current (in amperes) through R2 is
 A Fill in the Blank Type Question
Question 25 Explanation:
Let current through

Applying KVL,

Thus, current through
 Question 26
The switch S in the circuit shown has been closed for a long time. It is opened at time t = 0 and remains open after that. Assume that the diode has zero reverse current and zero forward voltage drop. The steady state magnitude of the capacitor voltage Vc (in volts) is ______
 A Fill in the Blank Type Question
Question 26 Explanation:

 Question 27
In the RLC circuit shown in the figure, the input voltage is given by

The output voltage Vo(t) is
 A Cos (200t) + 2sin (500t) B 2 cos (200t) + 4sin (500t) C Sin (200t) + 2cos (500t) D 2 sin (200t) + 4cos (500t)
Question 27 Explanation:

since there are 2 frequency term output will also have 2 frequency term.
If we take 4sin500t first i.e. W = 500 then on the output section, this parallel LC combination have so it is open circuit and V0 = Vi

So w.r.t. 4sin500t output must be 4sin500t without any change in amplitude and phase, this is satisfied by only option B.
 Question 28
The diodes D1 and D2 in the figure are ideal and the capacitors are identical. The product RC is very large compared to the time period of the ac voltage. Assuming that the diodes do not breakdown in the reverse bias, the output voltage V0 (in volt) at the steady state is ________.
 A Fill in the Blank Type Question
Question 28 Explanation:
 Question 29
Assume that the circuit in the figure has reached the steady state before time t = 0 when 3Ω the resistor suddenly burns out, resulting in an open circuit. The value of current i(t) (in ampere) through 2Ω resistor at t = 0+ is ______.
 A Fill in the Blank Type Question
Question 29 Explanation:
At the circuit is on steady state i.e. the capacitor is open circuited so the circuit will be

at t = 0+ when is open circuited, the capacitors will have an ideal voltage source of values 4V and 6V so the circuit will be

So the current through 2Ω resistor at t = 0+ should be 4/(2+2) = 1A
 Question 30
In the figure shown, the current i (in ampere) is ______.
 A Fill in the Blank Type Question
Question 30 Explanation:
Nodal equation at V

By using KCL at node ‘a’.

KCL at b
-
 Question 31
The z-parameter matrix for the two-port network shown in
 A B C D
Question 31 Explanation:
Since the given network is symmetric and reciprocal

And from the figure We get
 Question 32
For the circuit shown in the figure, the Thevenin equivalent voltage (in Volts) across terminals a-b is_____
 A Fill in the Blank Type Question
Question 32 Explanation:
 Question 33
The ABCD parameters of the following 2-port network are
 A B C D
Question 33 Explanation:
 Question 34
In the circuit shown, the current I flowing through the 50Ω resistor will be zero if the value of capacitor C(in μF) is ___________
 A Fill in the Blank Type Question
Question 34 Explanation:
Converting the circuit to phasor domain for AC analysis

If current I = 0,
Voltage at node A = input voltage
Applying KCL at node A,

or
Solving equation, we get
 Question 35
The position control of a DC servo-motor is given in the figure. The values of the parameters are KT = 1 N-m/A, Ra = 1W, La = 0.1 H, J = 5 kg-m2, B = 1 N-m/(rad/sec) and Kb = 1V/(rad/sec). The steady-state position response (in radians) due to unit impulse disturbance torque Td is _________
 A Fill in the Blank Type Question
Question 35 Explanation:
To find the response due to Td(s), we will use superposition making input Va (s) = 0 and finding
Transfer function
(unit impulse response)

But Td(s) is negative, so response is also negative, i.e. -0.5
 Question 36
Let the signal f(t) = 0 outside the interval T1, T2 where T1 and T2 are finite. Furthermore, . The region of convergence (ROC) of the signal’s bilateral Laplace transform F(s) is
1. A parallel strip containing the jΩ axis
2. A parallel strip not containing the jΩ axis
3. The entire s-plane
4. A half plane containing the jΩ axis
 A A B B C C D D
Question 36 Explanation:
Given, f (t) = 0 outside interval T1, T2.
and
So, it is a finite duration signal and for the finite duration signal ROC is always entire s-plane.
 Question 37
The 2-port admittance matrix of the circuit shown is given by
 A B C D
Question 37 Explanation:
 Question 38
The voltage (Vc) across the capacitor (in Volts) in the network shown is ______
 A 150 B 100 C 50 D 200
Question 38 Explanation:
 Question 39
In the circuit shown the average value of the voltage Vab (in Volts) in steady state condition is ______
 A 10 B 25 C 5 D 30
Question 39 Explanation:
 Question 40
In the circuit shown the average value of the voltage Vab (in Volts) in steady state condition is ______
 A 10 B 25 C 5 D 30
Question 40 Explanation:
 Question 41
An LC tank circuit consists of an ideal capacitor C connected in parallel with a coil of inductance L having an internal resistance R. The resonant frequency of the tank circuit is
 A B C D
Question 41 Explanation:
 Question 42
In the circuit shown, the Norton equivalent resistance across terminals a-b is ______.
 A 2.333 B 1.333 C 1.255 D 3.333
Question 42 Explanation:
 Question 43
Let x (t) = a s (t) + s (–t) with s (t) = βe–4t u (t), where u (t) is unit step function. If the bilateral Laplace transform of x (t) is

Then the value of β is _________
 A 2 B -2 C 1 D -1
Question 43 Explanation:
Given x(t) = αs(t) + s(–t)

Now, we have ROC Taking Laplace for given ROC, we have

Coefficient of s is zero. From above equation, we conclude the result as
 Question 44
For maximum power transfer between two cascaded sections of an electrical network, the relationship between the output impedance Z1 of the first section to the input impedance Z2 of the second section is
 A B C D
Question 44 Explanation:
consider the cascaded sections shown below

Z1 = First section Output impedance
Z2 = Second section Input impedance
For maximum power transfer, upto 1st section is
 Question 45

Consider the configuration shown in the figure which is a portion of a larger electrical network

For and currents i1=2A, i4=-1A, i5=-4A which one of the following is TRUE?

 A I6=5A B I3=-4A C Data is sufficient to conclude that the supposed currents are impossible D Data is insufficient to identify the current
Question 45 Explanation:
 Question 46

A Y-network has resistances of 10 Ω each in two of its arms, while the third arm has a resistance of 11 Ω in the equivalent D − network, the lowest value in Ω among the three resistances is ______________.

 A 25.09 B 27.09 C 28.09 D 29.09
Question 46 Explanation:

i.e, lowest value among three resistances is
 Question 47
A 230 V rms source supplies power to two loads connected in parallel. The first load draws 10 kW at 0.8 leading power factor and the second one draws 10 kVA at 0.8 lagging power factor. The complex power delivered by the source is
 A (18 + j 1.5) kVA B (18 - j 1.5) kVA C (20 + j 1.5) kVA D (20 - j 1.5) kVA
Question 47 Explanation:
 Question 48
A periodic variable x is shown in the figure as a function of time. The root-mean-square (rms) value of x is_______.
 A 0.324 B 0.368 C 0.408 D 0.442
Question 48 Explanation:
 Question 49
In the circuit shown in the figure, the value of capacitor C(in mF) needed to have critically damped response i(t) is____________.
 A 5 B 10 C 15 D 20
Question 49 Explanation:
Applying kirchoff’s voltage low in frequency domain, we have

Differentiate with respect to time,

For critically damped response,

This is the required value of C to have critically damped response i(t)
 Question 50
Norton’s theorem states that a complex network connected to a load can be replaced with an equivalent impedance
 A in series with a current source B in parallel with a voltage source C in series with a voltage source D in parallel with a current source
Question 50 Explanation:
Norton’s theorem states that a complex network connected to a load can be replaced with an equivalent impedance in parallel with a current source
 Question 51

A series LCR circuit is operated at a frequency different from its resonant frequency. The operating frequency is such that the current leads the supply voltage. The magnitude of current is half the value at resonance. If the values of L, C and R are 1 H, 1 F, and 1Ω, respectively, the operating angular frequency (in rad/s) is ________.

 A 0.25 B 0.3 C 0.4 D 0.45
Question 51 Explanation:

The operating frequencyat which current leads the supply.

again magnitude of current is half the value at resonance

By substituting R, L & C values,

So, operating frequency

 Question 52
In the h-parameter model of the 2-port network given in the figure shown, the value of h22 (in S) is _____ .
 A 1.24 B 1.28 C 1.32 D 1.36
Question 52 Explanation:
If two, are connected in parallel,

 Question 53
In the figure shown, the capacitor is initially uncharged. Which one of the following expressions describes the current I(t) (in mA) for t > 0?
 A B C D
Question 53 Explanation:
 Question 54
A series RC circuit is connected to a DC voltage source at time t = 0. The relation between the source voltage VS, the resistance R, the capacitance C, and the current i(t) is given below:

Which one of the following represents the current i(t)?
 A B C D
Question 54 Explanation:
 Question 55
In the figure shown, the value of the current I (in Amperes) is __________.
 A 0.2 Amp B 0.4 Amp C 0.5 Amp D 0.8 Amp
Question 55 Explanation:
 Question 56
In the circuit shown in the figure, the value of node voltage V2 is
 A B C D
Question 56 Explanation:
 Question 57
In the circuit shown in the figure, the angular frequency w (in rad/s), at which the Norton equivalent impedance as seen from terminals b-b' is purely resistive, is ________________.
 A 2r/s B 3 r/s C 4r/s D 5r/s
Question 57 Explanation:
Norton’s equivalent impedance

Equating imaginary term to zero i.e.,
 Question 58
For the Y-network shown in the figure, the value of in the equivalent -network is _______________.
 A 5 B 10 C 15 D 20
Question 58 Explanation:
 Question 59
The circuit shown in the figure represents a
 A Voltage controlled voltage source B Voltage controlled current source C Current controlled current source D Current controlled voltage source
Question 59 Explanation:

The dependent source represents a current controlled current source
 Question 60
The magnitude of current (in mA) through the resistor in the figure shown is_______.
 A 2.8 B 3.4 C 5 D 4.4
Question 60 Explanation:
 Question 61
In the circuit shown in the figure, the value of (in Volts) for
 A 21.25 B 25.5 C 31.25 D 35
Question 61 Explanation:
 Question 62
The equivalent resistance in the infinite ladder network shown in the figure is Re

The value of Re/R is ________
 A 2 B 2.618 C 4 D 4.618
Question 62 Explanation:

For an infinite ladder network, if all resistance are having same value of R
Then equivalent resistance is
For the given network, we can split in to R is in series with

 Question 63
For the two-port network shown in the figure, the impedance (Z) matrix (in ) is
 A B C D
Question 63 Explanation:
For the two-part network
 Question 64
A source has an internal impedance of . If a purely resistive load connected to this source has to extract the maximum power out of the source, its value in Ω should be
 A 3 B 4 C 5 D 7
Question 64 Explanation:
 Question 65
The following arrangement consists of an ideal transformer and an attenuator which attenuates by a factor of 0.8. An ac voltage VWX1 100 V is applied across WX to get an open circuit voltage VYZ1 across YZ. Next, an ac voltage VYZ2 = 100 V is applied across YZ to get an open circuit voltage VYZ2 across WX. Then are respectively
 A 125/100 and 80/100 B 100/100 and 80/100 C 100/100 and 100/100 D 80/100 and 80/100
Question 65 Explanation:
An ideal transformer is an imaginary transformer which has. - no copper losses (no winding resistance) - no iron loss in a core. - no leakage flux. In other words, an ideal transformer gives output power exactly equal to the input power.
Attenuator: a device consisting of an arrangement of resistors which reduces the strength of a radio or audio signal

Given transformer

Attenuation factor will be 0.8
So,
or,
at
at
 Question 66

Two magnetically uncoupled inductive coils have Q factors q1 and q2 at the chosen operating frequency. Their respective resistances are R1 and R2. When connected in series, their effective O factor at the same operating frequency is

 A B C D
Question 66 Explanation:
 Question 67
Three capacitors C1 C2 and C3 whose values are 10 µF. 5 µF. and 2 µF respectively, have breakdown voltages of 10V, 5V, and 2V respectively. For the interconnection shown below, the maximum safe voltage in Volts that can be applied across the combination, and the corresponding total charge
in µC stored in the effective capacitance across the terminals are respectively,
 A 2.8 and 36 B 7 and 119 C 2.8 and 32 D 7 and 80
Question 67 Explanation:
 Question 68
Consider the following figure

The current Is in Amps in the voltage source and voltage Vs in Volts across the current source respectively, are
 A 13, –20 B 8, –10 C –8, 20 D –13, 20
Question 68 Explanation:
 Question 69
The current in the 1 Ω resistor in Amps is(Continuation to above question)
 A 2 B 3.33 C 10 D 12
Question 69 Explanation:
 Question 70
The average power delivered to an impedance by a current is
 A 44.2 B 50 C 62.5 D 125
Question 70 Explanation:

W
 Question 71
The impedance looking into nodes 1 and 2 in the given circuit is
 A 50 Ω B 100 Ω C 5 kΩ D 10.1 k Ω
Question 71 Explanation:

To find thevenin impedance across node 1 and 2. Connect a 1 V source and find the current through voltage source.
Then
By applying KCL at node B and A
iAB + 99ib = ITh
ib = iA + IAB
⇒ ib – iA + 99ib = ITh
⇒ 100ib – iA = iTh …(1)
By applying KVL in outer loop
10 × 103ib = 1
ib = 10-4 A
And 10 × 103ib = -100iA
⇒ iA = -100iA
From equation (i)
100iA + 100ib = ITh
⇒ ITh = 200ib
⇒ 200 × 104 = 0.02
 Question 72
In the circuit shown below, the current through the inductor is
 A B C D 0 A
Question 72 Explanation:
 Question 73
Assuming both the voltage sources are in phase, the value of R for which maximum power is transferred from circuit A to circuit B is
 A 0.8 Ω B 1.4 Ω C 2 Ω D 2.8 Ω
Question 73 Explanation:
Current through R will be

Current through 3 V source is

So power delivered to circuit B by circuit A is
P = i2R + i1 × 3

for P to be maximum will be aero

49(2+R) – 98R – 21(2+R) = 0
98 + 42 = 49R + 21R
 Question 74
If VA – VB = 6V, then VC - VD is
 A –5V B 2V C 3V D 6V
Question 74 Explanation:

= 3A …(1)
KCL at node B, we have
i = i2 + i1
i2 + i1 = 3A ..(2)
KCL at node E, we have
i1 = i3 + i4 …(3)
KCL at node D we have
i5 = i2 + i3 + i4
i5 = i2 + i1
i5 = 3A
KCL at node F, we have
i6 + 2 + i5 = 0
i6 = -2-i5
So, VC – VD = 1 × i6 = -5V
 Question 75
With 10 V dc connected at port A in the linear nonreciprocal two-port network shown below, the following were observed:
(i) 1 Ω connected at port B draws a current of 3 A
(ii) 2.5 Ω connected at port B draws a current of 2 A

With 10 V dc connected at port A. the current drawn by 7 Ω connected at port B is
 A 3/7 A B 5/7 A C 1A D 9/7 A
Question 75 Explanation:

IL = VTh / (RTh +RL)

(i) RL=1 Ω, IL =3A,

Implies 3 = VTh / (RTh +1),

(ii) For RL=2.5 Ω, IL = 2A.

Implies 2= VTh / (RTh +2.5)

Divide above equations (i) and (ii),

3/2 = (RTh + 2.5)/ (RTh + 1),

3 RTh + 3 = 2 RTh + 5.

RTh = 2 Ω.

Substitute  RTh in the above equation, VTh = 3(2+1) = 9V.

For RL=7 Ω, IL= VTh(2+RL) = 9/(2+7) = 1A

 Question 76
What is the condition for reciprocity and symmetry in Y-parameter representation?
 A Y21 = Y11 and Y22 = Y21 B Y21 = Y12 and Y11 = Y22 C Y21 = Y22 and Y11 = Y22 D Y11 = Y22 and Y21 = Y22
Question 76 Explanation:
 Question 77
In hybrid parameters, h11 and h21 are called as
 A input impedance and forward current gain B reverse voltage gain and output admittance C input impedance and reverse voltage gain D output impedance and forward current gain
Question 77 Explanation:

V1 = h11 I1 + h12 V2
I2 = h21 I1 + h22 V2

h11 is input impedance

h21 is forward current gain
Option A
 Question 78
Consider the following equations:
V1 = 6V2 – 4I2
I1 = 7V2 – 2I2
A, B, C and D parameters are
 A 6,-4 Ω, 7 mho and -2 B 6, 4 Ω, 7 mho and 2 C -6, 4 Ω, -7 mho and 2 D 6, 4 Ω, -7 mho and -2
Question 78 Explanation:
 Question 79
A supply of 250 V, 50 Hz is applied to a series RC circuit. If the power absorbed by the resistor be 400 W at 160 V, the value of the capacitor C will be nearly
 A 30.5 μF B 41.5 μF C 64.0 μF D 76.8 μF
Question 79 Explanation:

PR = 400 watt
VR = 160 V

 Question 80
A 50 Hz sinusoidal voltage V = 311 sin ωt is applied to an RL series circuit. If the magnitude of resistance is 5 Ω and that of the inductance is 0.02 H, the r.m.s. value of the steady-state current and the relative phase angle are nearly
 A 19.6 A and 51.5o B 27.4 A and -51.5o C 19.6 A and -51.5o D 27.4 A and 51.5o
Question 80 Explanation:
 Question 81
In a series RC circuit, the values of R = 10 Ω and C = 25 nF A. sinusoidal voltage of 50 MHZ is applied and the maximum voltage across the capacitance is 2.5 V. The maximum voltage across the series combination will be nearly
 A 172.7 V B 184.5 V C 196.3 V D 208.1 V
Question 81 Explanation:
 Question 82
The peak-to-peak ripple voltage for a half-wave rectifier and filter circuit operating at 60 Hz, which has a 680 μF reservoir capacitor, an average output of 28 V and 200 load resistance, will be nearly
 A 2.5 V B 3.4 V C 4.3 V D 5.2 V
Question 82 Explanation:
Given frequency, f = 60Hz
C = 680μF = 28V
Voutput average = 28V
RL = 200Ω
Charge stored while charging = charge discharged while discharging
× C = IDC × To

= 3.4 V
Option B
 Question 83
A steady state is achieved in following Network at T = 0, find the time when Vc(t) will be maximum
 A In(9) sec B ln(9)0.125 sec C ln(9)0.25 sec D 9 sec
Question 83 Explanation:
The Correct Answer Among All the Options is B
Taking laplace transform of given circuit then finding the voltage across capacitor . then after using of concept of maxima/minima , we get the time when Vc(t) will be maximum i.e. t=ln(9)0.125 sec
Refer the Topic Wise Question for Time Domain and Frequency Analysis of Linear circuits Networks
 Question 84
Y-parameter for following network is given as
 A B C D
Question 84 Explanation:
The Correct Answer Among All the Options is C
for parallel connection Y-parameters will be added , from the given figure we can observe that given circuit is symmetrical and reciprocal.
We can split the given circuit in two equivalent circuit which are connected in parallel.

Y-parameters for this circuit will be :
=
=
=

2nd circuit consist of only capacitors., it is also a reciprocal and symmetrical circuit, Y-parameters for this circuit will be

=
=
=
=
On adding these two parameters , we get eqivalent Y-parameter.
Refer the Topic Wise Question for Two Port Networks Networks
 Question 85
Two resistances of values 2 and 4 made of different materials with temperature cofficients of resistance 3 ppm/0C and 6 ppm/0C respctively are connected in series. What is the temperature coefficient of resistance of the nt resistance?
 A 5 ppm/0C B ppm/0C C 9 ppm/0C D 4.5 ppm/0C
Question 85 Explanation:
The Correct Answer Among All the Options is A

are temperature coefficient of respectively.
When are connected in series. Then
(1+) ,
where ,
equivalent temperature coefficient
= +
=
Given ,

On putting these values ,
Refer the Topic Wise Question for Basic Electrical Engineering Networks
 Question 86
An LC tank circuit resonates at a frequncy ‘fr’. If the temperature coefficient of prmittivity of the dielectric material used in the Capacitance is 6 ppm/0C, then what is the temperature coefficient of frequency ‘fr’.
 A -3 ppm/0C B 3 ppm/0C C -6 ppm/0C D 6 ppm/0C
Question 86 Explanation:
The Correct Answer Among All the Options is A
Formula for resonance frequency in LC tank circuit =
Differentiate .r.t temperature(T), only Capacitance will vary because here temperature coefficient of (permittivity ) is given.
= …………………. (1)
And C=C[1+], from this …………………. ..(2)
From (1) and (2)
= , on simplifying it we get

Now as we know for any change in temperature(), new frequency will be

=
=
This equation shows that temperature coefficient of will be .
Given,6ppm
Therefore, =
= -3ppm/.
Refer the Topic Wise Question for Steady State equations and Analysis Networks
 Question 87
For a circuit given in figure, switch K is closed to position 1 at t = 0. After t = 1 TC (Time Constant), switch is moved to position 2. Find the Current I at 1TC(-) (just before on-time constant time) and ITC(+) (just after one-time constant time) respctively (assum 1/e 0.37)
 A 0.0148 A and 0.055 A B 0.0148 A and -0.055 A C 0.0296 A and 0.11 A D 0.0296 A and -0.11 A
Question 87 Explanation:
The Correct Answer Among All the Options is A
For 0 < t < 1 time constant()
, switch is connected to “1”. Therefore circuit becomes,

=RC
=500
= 2.5 econds
So the capacitor slowly charges to 20V with following equation

At t=,
=
= 20[1-0.37]
=12.6 V
i.e At , the capacitor voltage is = 12.6 V
I at = =0.0148A
After 1 time constant () i.e. at t=, equivalent circuit becomes

Therefore, I =
=
= 0.0548A
Refer the Topic Wise Question for Time Domain and Frequency Analysis of Linear circuits Networks
 Question 88
For a network shown in figure, which of the following statement is true.
 A Reciprocal and symmetric B Rciprocal but not-symmetric C Symmetric but non-rciprocal D Neither symmetric nor reciprocal
Question 88 Explanation:
The Correct Answer Among All the Options is D
Normally we know dependent source make a circuit non-reciprocal. As for symmetrical circuit , there should be mirror image in circuit , but in figure we can clearly see that there is no any line of symmetry. So given circuit is Non-reciprocal and not symmetric.
To check we have to calculate Z-parameter.

When

+
When

+ =

not symmetrical
not reciprocal
Refer the Topic Wise Question for Two Port Networks Networks
 Question 89
For a network shown in figure, Calculate current i2.
 A 2/3 A B 3/2 A C 1/3 A D None of the above
Question 89 Explanation:
The Correct Answer Among All the Options is A
In the given circuit , we can use superposition principle. While using the voltage source current source is open circuited, and while using the current source voltage source is short circuited.
And calculate
Refer the Topic Wise Question for Network Equations and Solution Methods Networks
 Question 90
For a network shown in figure, a steady state is reached with switch k is open. Switch is closed at time t = 0. Calculate (di1/dt) and (di2/dt) at t = 0+
 A 16.67 A/sec and -4.16 x 104 A/sec B 16.67 A/sec and -3.33 x 104 A/sec C 25 A/sec and -4.16 x 104 A/sec D 25 A/sec and -3.33 x 104 A/sec
Question 90 Explanation:
The Correct Answer Among All the Options is A

Inductor short circuit ,
Capacitor open circuit, 0A

=

=
Inductor does not allow sudden change in current and capacitor does not allow sudden change in voltage.
So and
The equivalent circuit at t=is,

Where ,
Also,

=v
For inductor,

=
= 16.67 A/sec
KVL for capacitor branch,
100V=
On differentiating w.r.t ‘t’
0=20 + …………………………..(1)
Also, =
Also., C = ………….(2)
Put (2) in (1)
0= 20
Given, C=2
=-4.16
= =-4.16 A/s
Refer the Topic Wise Question for Steady State equations and Analysis Networks
 Question 91
Identify the correct sequence of stages in charging of a Lead-Acid battery.
 A Constant Current, Topping, Float B Topping, Constant Current, Float C Float, Topping, Constant Current D Float, Constant Current, Topping
Question 91 Explanation:
The Correct Answer Among All the Options is A
The lead acid battery uses the constant current constant voltage (CC/CV) charge method. A regulated current raises the terminal voltage until the upper charge voltage limit is reached, at which point the current drops due to saturation. Lead acid batteries should be charged in three stages, which are [1] constant-current charge, [2] topping charge and [3] float charge. The constant-current charge applies the bulk of the charge and takes up roughly half of the required charge time; the topping charge continues at a lower charge current and provides saturation, and the float charge compensates for the loss caused by self-discharge.
Refer the Topic Wise Question for Basic Electrical Engineering Networks
 Question 92
For the circuit shown below, Z1=K1 x (s+2)/(s+5). Find Z2, where K1 and K2 are constants containing circuit' element values
 A K2 x s/(s + 5) B (s + 5)/(s x K2) C K2 x s/(s + 6) D (s 6)/(s x K2)
Question 92 Explanation:
The Correct Answer Among All the Options is A
Given=> Z1= K1 [(s+2)/(s+5)]
Now, We have to determine what is Z2. Now according to general concept, Z2 can be written as: Ls||(R1+R2)
This can also be written as: (R1+R2)Ls/Ls+R1+R2.................(a)
Now given options are having 'K' term in them. It means we have to bring Z1 in the scenario.
So, given=> Z1= K1 (s+2)/(s+5)
Now in order to get R1, R2 and Ls in terms of K, we have to reduce Z1 and bring it in a form so that it can be compared with the Z1 given in the question.
Now looking at the figure we can write:
Z1= R1||(R2+Ls)=> R1(R2+Ls)/R1+R2+Ls
So, we have to bring it in a particular form.
Now=> in question's Z1 term=> 's+' term is present. It means that we have to somehow take Ls common from here. So taking Lcommon so that 's' remains inside the bracket.
So on taking 'L' term out, and simplifying we will get: Z1= (R2/L +s)R1 / (R1+R2)/L +s
Now this can easily be compared with Z1 given in question. On comparing, we get:
R1=K1, R2/L=2
So, now putting these values in (a) we get:
Z2= (R1+R2)Ls/Ls+R1+R2
=> L(R1+R2)(s)/ R1+R2/L +s
Now, R1+R2/L=5(From comparing), R1=K1, and R1/L=3.
So, on putting this, we will get Z2= sK/(s+5)
Refer the Topic Wise Question for Two Port Networks Networks
There are 92 questions to complete.