EC GATE 2011 (Test 2)



Tag: ec gate 2011
Q.1
The question below consists of a pair of related words followed by four pairs of words. Select the pair that best expresses the relation in the original pair: Gladiator : Arena
A. dancer : stage
B. commuter: train
C. teacher : classroom
D. lawyer : courtroom
Answer : Option A
Explaination / Solution:

A gladiator performs in an arena. Commutators use trains. Lawyers performs, but do not entertain like a gladiator. Similarly, teachers educate. Only dancers performs on a stage.

Workspace
Report
Topic: Arithmetic Tag: EC GATE 2011
Q.2
The fuel consumed by a motorcycle during a journey while traveling at various speeds is indicated in the graph below.

The distances covered during four laps of the journey are listed in the table below

From the given data, we can conclude that the fuel consumed per kilometre was least during the lap
A. P
B. Q
C. R
D. S
Answer : Option B
Explaination / Solution:

Since fuel consumption/litre is asked and not total fuel consumed, only average speed is relevant. Maximum efficiency comes at 45 km/hr, So least fuel consumer per litre in lap Q

Workspace
Report
Q.3
Two D flip-flops are connected as a synchronous counter that goes through the following QBQsequence 00⟶11⟶01⟶10⟶00⟶… The combination to the inputs DA and DB are
A.
B.
C.
D.
Answer : Option D
Explaination / Solution:

The sequence is QBQA
00⟶11⟶01⟶10⟶00⟶…




Workspace
Report
Q.4
Drift current in the semiconductors depends upon
A. only the electric field
B. only the carrier concentration gradient
C. both the electric field and the carrier concentration
D. both the electric field and the carrier concentration gradient
Answer : Option C
Explaination / Solution:
No Explaination.


Workspace
Report
Q.5
For the BJT QL in the circuit shown below,  The switch is initially closed. At time t = 0, the switch is opened. The time t at which Q1 leaves the active region is

A. 10 ms
B. 25 ms
C. 50 ms
D. 100 ms
Answer : Option C
Explaination / Solution:


Applying KCL at collector

with time, the capacitor charges and voltage across collector changes from 0 towards negative.


Workspace
Report
Q.6
A transmission line of characteristic impedance 50Ω is terminated by a 50 W load. When excited by a sinusoidal voltage source at 10 GHz, the phase difference between two points spaced 2 mm apart on the line is found to be π/4 radians. The phase velocity of the wave along the line is
A.

0.8 × 108 m/s

B.

1.2 × 108 m/s

C.

1.6 × 108 m/s

D.

3 × 108 m/s

Answer : Option C
Explaination / Solution:

We have d = 2 mm and f = 10 GHz


Workspace
Report
Q.7
A message signal m(t) = cos 200πt + 4cosπt  modulates the carrier c(t) = coe 2πfct where fc = 1MHz to produce an AM signal. For demodulating the generated AM signal using an envelope detector, the time constant RC of the detector circuit should satisfy
A. 0.5 ms < RC < 1 ms
B. 1 μs << RC < 0.5 ms
C. RC << μs
D. RC >> 0.5 ms
Answer : Option B
Explaination / Solution:

Highest frequency component in m(t) is 
Carrier frequency fc = 1 MHz
For Envelope detector condition


Workspace
Report
Q.8
The root locus plot for a system is given below. The open loop transfer function corresponding to this plot is given by


A.
B.
C.
D.
Answer : Option B
Explaination / Solution:

For given plot root locus exists from -3 to , So there must be odd number of poles and zeros. There is a double pole at s = - 3
Now poles = 0, -2, -3, -3
zeros = - 1
Thus transfer function 

Workspace
Report
Q.9
The input-output transfer function of a plant  The plant is placed in a unity negative feedback configuration as shown in the figure below. 
The signal flow graph that DOES NOT model the plant transfer function H(S) is

A.
B.
C.
D.
Answer : Option D
Explaination / Solution:



Workspace
Report
Q.10
Consider a closed surface S surrounding volume V. If  is the position vector of a point inside S, with  the unit normal on S, the value of the integral  is
A. 3V
B. 5V
C. 10V
D. 15V
Answer : Option D
Explaination / Solution:

From Divergence theorem, we have

The position vector 

Here, , thus


Workspace
Report