Electronics Engineering - Online Test
Q1. 
Consider the common emitter amplifier shown below with the following circuit parameters:
The lower cut-off frequency due to C2 is
Answer : Option B
Explaination / Solution:
Cut-off frequency due to C2
Lower cut-off frequency
Q2. The complete set of only those Logic Gates designated as Universal Gates is
Answer : Option C
Explaination / Solution:
No Explaination.
Q3. In a p n junction diode under reverse biased the magnitude of electric field is maximum at
Answer : Option C
Explaination / Solution:
The electric field has the maximum value at the junction of p n.
Q4. A three-winding transformer is connected to an AC voltage source as shown in the figure.
The number of turns are as follows: N1 = 100, N2 = 50. If the magnetizing current is
neglected, and the currents in two windings are 
and 
then
what is the value of the current 
in Ampere?
and then
what is the value of the current in Ampere?
Answer : Option A
Explaination / Solution:
Q5. A second-order real system has the following properties:
a) the damping ratio ς = 0.5 and undamped natural frequency ωn =10 rad/s
b) the steady state value of the output, to a unit step input, is 1.02.
The transfer function of the system is
Answer : Option B
Explaination / Solution:
Q6. Consider the system with following input-output relation
where, x[n] is the input and y[n] is the output. The system is
where, x[n] is the input and y[n] is the output. The system is
Answer : Option D
Explaination / Solution:
Q7. 
In the circuit shown below what is the output voltage (vout)if a silicon transistor Q and an ideal op-amp are used?
Answer : Option B
Explaination / Solution:
For the given ideal op-amp, negative terminal will be also ground (at zero voltage) and so, the collector terminal of the BJT will be at zero voltage.
i.e., VC = 0 volt
The current in 1 kΩ resistor is given by
This current will flow completely through the BJT since, no current will flow into the ideal op-amp (I/P resistance of ideal op-amp is infinity). So, for BJT we have
i.e.,the base collector junction is reverse biased (zero voltage) therefore, the collector current (IC ) can have a value only if base-emitter is forward biased.
Hence,
Q8. Which of the following statements is true regarding the fundamental mode of the metallic waveguides shown ?
Answer : Option A
Explaination / Solution:
Rectangular and cylindrical waveguide doesn’t support TEM modes and have cut off frequency. Coaxial cable support TEM wave and doesn’t have cut off frequency.
Q9. 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
is the position vector
of a point inside S, with the unit normal on S, the value of the integral is
Answer : Option D
Explaination / Solution:
From Divergence theorem, we have
The position vector
Here, 
, thus
, thus
Q10. In an 8085 microprocessor, the contents of the Accumulator, after the following instructions are executed will become
XRA A
MVI B, F0H
SUB B
Answer : Option D
Explaination / Solution:
