Electrical Engineering - Online Test
Q1. The current I in the circuit shown is
Answer : Option A
Explaination / Solution:
Q2. A continuous time LTI system is described by
Assuming zero initial conditions, the response y(t) of the above system for the input 
is given by
is given by
Answer : Option B
Explaination / Solution:
System is described as
Taking laplace transform on both side of given equation
Transfer function of the system
By Partial fraction
Taking inverse laplace transform
Q3.
A unity negative feedback closed loop system has a plant with the transfer function 
and a controller GC (s) in the
and a controller GC (s) in thefeed forward path. For a unit set input, the transfer function of the controller that gives minimum steady state error is
Answer : Option D
Explaination / Solution:
Steady state error is given as
ess will be minimum if 
is maximum In option (D)
is maximum In option (D)
Q4. In the circuit shown below, the knee current of the ideal Zener dioide is 10 mA
. To maintain 5 V across RL, the minimum value of RL in Ω and the minimum
power rating of the Zener diode in mW, respectively, are
Answer : Option B
Explaination / Solution:
No Explaination.
Q5. The system of linear equations
4x + 2y = 7
2x + y = 6 has
Answer : Option B
Explaination / Solution:
Q6. If X = 1 in logic equation 
Then
Then
Answer : Option D
Explaination / Solution:
Substituting X = 1 and
we get
1 + A = 1 and 0 + A = A
Substituting X = 1 and
we get 1 + A = 1 and 0 + A = A
Q7. x(t) is a stationary random process with auto-correlation function. 
This process is passed through the system shown below. The
power spectral density of the output process y(t) is
This process is passed through the system shown below. The
power spectral density of the output process y(t) is
Answer : Option A
Explaination / Solution:
The given circuit can be simplified as
Power spectral density of output is
Q8. In the circuit shown, the power supplied by the voltage source is
Answer : Option A
Explaination / Solution:
Applying nodal analysis
Current from voltage source is
Since current through voltage source is zero, therefore power delivered is zero.
Q9. The signal flow graph of a system is shown below:
The state variable representation of the system can be
Answer : Option D
Explaination / Solution:
Q10. 
Consider a single input single output discrete-time system with x[n] as input and y[n] as output, where the two are related as
Which one of the following statements is true about the system?
Answer : Option A
Explaination / Solution:
For an input-output relation if the present output depends on present and past input values then the given system is “Causal”.
For the given relation,
For n ranging from 0 to 10 present output depends on present input only.
At all other points present output depends on present and past input values.
Thus the system is “Causal”.
Stability
If x[n] is bounded for the given finite range of n i.e. 0 ≤ n ≤ 10 y[n] is also bounded.
Similarly x[n] - x[n-1] is also bounded at all other values of n
Thus the system is “stable”.
