EC GATE 2014 PAPER 01 - Online Test
Q1. Choose the most appropriate phrase from the options given below to complete the following sentence.
The aircraft _____ take off as soon as its flight plan was filed
Answer : Option C
Explaination / Solution:
No Explaination.
Q2. Choose the most appropriate word from the options given below to complete the following sentence.
Many ancient cultures attributed disease to supernatural causes. However, modern science has largely helped______such notions.
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. The force on a point charge +q kept at a distance d from the surface of an infinite grounded metal plate in a medium of permittivity 𝜖 i
Answer : Option C
Explaination / Solution:
Consider the point charge +q and infinite surface as shown below.
We can replace the image charge by a negative equivalent charge -q placed at
2d distance from +q charge
Hence, the force experienced by +q charge is
Q4. A good current buffer has
Answer : Option B
Explaination / Solution:
No Explaination.
Q5. In the ac equivalent circuit shown in the figure, if iin is the input current and Rf is very larger, the type of feedback is
Answer : Option B
Explaination / Solution:
From the circuit, we observe that output is Vout (Voltage). Feedback is current
through resistance Rf , which is added to input current iin . Thus, the configuration
is voltage-current feedback.
Q6. In the circuit shown, the op-amp has finite input impedance, infinite voltage
gain and zero input offset voltage. The output voltage Vout is
Answer : Option C
Explaination / Solution:
Given that the op-amp has infinite voltage gain, i.e.
AOL =
and zero input offset voltage
VIO = 0
So, we redraw the op-amp circuit as
Hence, the current I1 is drawn through resistance R2. So, the output voltage is
Vout = I1R2
Q7. In the figure, assume that the forward voltage drops of the PN diode D1 and
Schottky diode D2 are 0 7. V and 0 3. V, respectively. If ON denotes conducting
state of the diode and OFF denotes non-conducting state of the diode, then in
the circuit,
Answer : Option D
Explaination / Solution:
Alternatively, we can solve the problem by considering the current through two
diodes. Here, the correct case is only considered. 
Case : Diode D1 is OFF, D2 is ON. For this case. The equivalent circuit is
From the circuit, we have
I1 = 0
I2 = 10 - 2.3/1.02
= 9.7/1.02
= 9.5 mA
Since, the current I2 is positive, So our assumption is correct.
Q8. If fixed positive charges are present in the gate oxide of an n-channel enhancement type MOSFET, it will lead to
Answer : Option A
Explaination / Solution:
If fixed positive charges are present is the gate oxide of an n-channel enhancement type MOSFET, it will lead to a decrease in the threshold voltage.
Q9. In the following circuit employing pass transistor logic, all NMOS transistors
are identical with a threshold voltage of 1 V . Ignoring the body-effect, the
output voltages at P, Q and R are,
Answer : Option C
Explaination / Solution:
No Explaination.
Q10. The doping concentrations on the p-side and n-side of a silicon diode are 1 × 1016 cm-3 and 1 × 1017 cm-3, respectively. A forward bias of 0 3. V is
applied to the diode. At T = 300 K, the intrinsic carrier concentration of silicon ni = 1.5 × 1010 cm-3 and (kT/q) = 26 mV. The electron concentration at the edge of
the depletion region on the p-side is
Answer : Option A
Explaination / Solution:
Given the doping concentration on p-side
NA = 1 × 1016 cm-3
V = 0.3 V
Intrinsic carrier concentration,
So, the equilibrium electron concentration on the p-side is
Therefore, the electron at the edge of the depletion region on the p-side is obtained
as
