Electronics Engineering - Online Test
Q1. The
field (in A/m) of a plane wave propagating in free space is given by
field (in A/m) of a plane wave propagating in free space is given byThe time average power flow density in Watts is
Answer : Option D
Explaination / Solution:
Q2. For a Hertz dipole antenna, the half power beam width (HPBW) in the E-plane is
Answer : Option C
Explaination / Solution:
The beam-width of Hertizian dipole is 1800 and its half power beam-width is 900
Q3. Consider the following circuit using an ideal OPAMP. The I-V characteristic of
the diode is described by the relation 
where VT = 25 mV, I0 = 1μ A and V is the voltage across the diode (taken as positive for forward bias). For
an input voltage Vi = -1 V, the output voltage V0 is
where VT = 25 mV, I0 = 1μ A and V is the voltage across the diode (taken as positive for forward bias). For
an input voltage Vi = -1 V, the output voltage V0 is
Answer : Option B
Explaination / Solution:
Q4. 
Consider a delta connection of resistors and its equivalent star connection as shown below. If all elements of the delta connection are scaled by a factor k, k>0, the elements of the corresponding star equivalent will be scaled by a factor of
Answer : Option B
Explaination / Solution:
No Explaination.
Q5. An ammeter has a current range of 0-5A, and its internal resistance is 0.2Ω. In order to change
the range to 0-25A, we need to add a resistance of
Answer : Option D
Explaination / Solution:
No Explaination.
Q6. The transfer function 
of the circuit shown below is
of the circuit shown below is
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. The state variable formulation of a system is given as 
The response y(t) to the unit step input is
Answer : Option A
Explaination / Solution:
No Explaination.
Q8. When a bipolar junction transistor is operating in the saturation mode, which one of the following statement is TRUE about the state of its collector-base (CB) and the baseemitter (BE) junctions?
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. A Boolean function f(A,B,C,D) = ∏(1,5,12,15) is to be implemented using an 8×1
multiplexer (A is MSB). The inputs ABC are connected to the select inputs S2S1S0 of the
multiplexer respectively. 
Which one of the following options gives the correct inputs to pins 0,1,2,3,4,5,6,7 in order?
Answer : Option B
Explaination / Solution:
Q10. Consider the following combinational function block involving four Boolean variables x, y, a,
b where x, a, b are inputs and y is the output.
f (x, y, a, b)
{
if (x is 1) y = a;
else y = b;
}
Which one of the following digital logic blocks is the most suitable for implementing this
function?
Answer : Option C
Explaination / Solution:
‘x’ is working as selection line, where the two input lines are ‘a’ and
‘b’, so the function F (x, y,a,b) can be implemented using (2× 1)
multiplexer as follows:
