2014
1.
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)
Z2
= Z1
b)
Z2
= –
Z1
c)
Z2
= Z1*
d)
Z2
= –
Z1*
2.
Consider the configuration shown in the figure, which is a portion
of a larger electrical network. For R = 1 Ω
and
currents i1
= 2A, i4
= –
1A, i5
= –
4A, which one of the follwoing is TRUE?
a)
i6
= 5 A
b)
i3
= –
4 A
c)
Data
is sufficient to conclude that the supposed currents are impossible
d)
Data
is insufficient to identify the currents i2,
i3
and i6
3.
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 Δ
– network,
the lowest value (in Ω)
among the three resistances is _________
4.
A 230 volts rms source supplies power to two loads connected in
parallel. The first load draws 10kW 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
5.
A
periodic variable x is shown in the figure as a function of time.
The
root-mean-square (rms) value of x is _________________
6.
In the circuit shown in the figure, the value of capacitor C (in mF)
needed to have critically damped response i(t) is
____________________
7.
Norton's theorem states that a complex network connected to a load
can be replaced with an equivalence 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
8.
In the figure shown, the ideal switch has been open for a long time.
If it is closed at t = 0, then the magnitude of the current (in mA)
through the 4 kΩ
resistor
at t = 0+
is ____________
9.
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 1H, 1F and 1Ω
respectively,
then the opeating angular frequency (in rad/sec) is
____________________
10.
In the h – parameter model of 2 – port network given in the
figure shown,
the value of h22
(in siemens) is _____________
11.
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 ?
12.
In the magnetically coupled circuit shown in the figure, 56% of the
total flus emanating from one coil links the other coil.
The value of
the mutual inductance (in H) is _________________
13.
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) ?
14.
In the figure shown, the value of the current I (in Amperes) is
______________
15.
Consider the building block called 'Network N' shown in the figure.
Let C = 100 µF
and R = 10 kΩ.
Two
such blocks are connected in cascade, as shown in the figure,
find
the transfer function V3(s)/V1(s)
of the cascaded network is
16.
In the circuit shown in the figure, the value of node voltage V2
(in volts) is
a)
22
+ j 2
b)
2
+ j 22
c)
22
– j 2
d)
2
– j 22
17.
In the circuit shown in the figure, the angular frequency ω (in
rad/sec), at which the Norton equivalent impedance as seen from
terminals b – b' is purely resistive, is _____________
18.
For the Y – network shown in the figure, the value of R1
(in Ω)
in the equivalent Δ
– network
is ____
19.
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
20.
The magnitude of current (in mA) through the resistor R2
in the figure shown is ___________
21.
The steady state output of the circuit shown in the figure is given
by y(t) = A(ω) sin(ωt + φ(ω)).
If the amplitude |A(ω)| = 0.25,
then the frequency ω is
22.
In the circuit shown in the figure,
the value of Vo(t)
(in volts) for t →
∞ is ___________
23.
The equivalent resistance in the infinite ladder network shown in
the figure is Re.
The value of Re/R
is ________________
24.
For the two – port network shown in the figure, the impedance (Z)
matrix (in Ω)
is
