Electronics Engineering - Online Test
Q1. The impulse response of a continuous time system is given by 
The value of the step response at t = 2 is
The value of the step response at t = 2 is
Answer : Option B
Explaination / Solution:
Q2. An LTI system having transfer function 
and input x(t) = sin(t + 1) is in steady state. The output is sampled at a rate ws rad/s to obtain the final output {x(k)}. Which of the following is true ?
and input x(t) = sin(t + 1) is in steady state. The output is sampled at a rate ws rad/s to obtain the final output {x(k)}. Which of the following is true ?
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. In the circuit shown below, the Norton equivalent current in amperes with
respect to the terminals P and Q is
Answer : Option A
Explaination / Solution:
Replacing P - Q by short circuit as shown below we have
Using current divider rule the current ISC is
Q4. Two D flip-flops are connected as a synchronous counter that goes through the
following QBQA sequence 00⟶11⟶01⟶10⟶00⟶… The combination to the inputs DA and DB are
Answer : Option D
Explaination / Solution:
The sequence is QBQA
00⟶11⟶01⟶10⟶00⟶…
Q5. The unit step response of an under-damped second order system has steady state value of -2. Which one of the following transfer functions has theses properties ?
Answer : Option B
Explaination / Solution:
For under-damped second order response
Q6. In the circuit shown below, the value of RL such that the power transferred to RL is maximum is
Answer : Option C
Explaination / Solution:
Power transferred to RL will be maximum when RL is equal to the thevenin
resistance. We determine thevenin resistance by killing all source as follows :
Q7. An 8085 assembly language program is given below. Assume that the carry
flag is initially unset. The content of the accumulator after the execution of the
program is
Answer : Option C
Explaination / Solution:
Initially Carry Flag, C = 0
MVI A, 07 H ; A = 0000 0111
RLC ; Rotate left without carry. A = 00001110
MVO B, A ; B = A = 00001110
RLC ; A = 00011100
RLC ; A = 00111000
ADD B ; A = 00111000
; +00001110
; 01000110
RRC ; Rotate Right with out carry, A = 0010 0011
Thus A = 23 H
Q8. For the following feedback system 
The 2% settling time of the
step response is required to be less than 2 seconds.
The 2% settling time of the
step response is required to be less than 2 seconds.
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. In the circuit shown below, the current I is equal to
Answer : Option B
Explaination / Solution:
From star delta conversion we have
Replacing in circuit we have the circuit shown below :
Now the total impedance of circuit is
Q10. The first six points of the 8-point DFT of a real valued sequence are 5, 1 - j3, 0, 3 - 4j, 0 and 3 + 4j .....The last two points of the DFT are respectively
Answer : Option B
Explaination / Solution:
For 8 point DFT, 
and it is conjugate
symmetric about x[4], x[6] = 0; x[7] = 1 + j3
and it is conjugate
symmetric about x[4], x[6] = 0; x[7] = 1 + j3