Electrical Engineering - Online Test
Q1. In the given network V1 = 100∠0°V, V2 = 100∠-120°V, V3 = 100∠+120°V. The phasor
current i (in Ampere) is
Answer : Option A
Explaination / Solution:
Q2. The Laplace Transform of f(t) = e2t sin(5t) u(t) is
Answer : Option A
Explaination / Solution:
Q3. 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
Q4. The open loop transfer function of a unity feedback control system is given by
The closed loop system will be stable if,
Answer : Option C
Explaination / Solution:
Q5. Let z(t) = x(t) * y(t), where "*" denotes convolution. Let C be a positive real-valued constant. Choose the correct expression for z (ct).
Answer : Option A
Explaination / Solution:
Q6. Consider the following statements regarding the complex Poynting vector 
for
the power radiated by a point source in an infinite homogeneous and lossless
medium. Re(
) denotes the real part of 
denotes a spherical surface whose
centre is at the point source, and 
denotes the unit surface normal on S.
Which of the following statements is TRUE?
for
the power radiated by a point source in an infinite homogeneous and lossless
medium. Re() denotes the real part of denotes a spherical surface whose
centre is at the point source, and denotes the unit surface normal on S.
Which of the following statements is TRUE?
Answer : Option C
Explaination / Solution:
Power radiated from any source is constant.
Q7. A speed signal, band limited to 4 kHz and peak voltage varying between +5 V and -5 V, is sampled at the Nyquist rate. Each sample is quantized and represented by 8 bits.
If the bits 0 and 1 are transmitted using bipolar pulses, the minimum bandwidth required for distortion free transmission is
Answer : Option B
Explaination / Solution:
Q8. Power is transferred from system A to system B by an HVDC link as shown in the figure. If the
voltages VAB and VCD are as indicated in the figure, and I > 0, then
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. 
A separately excited dc machine is coupled to a 50Hz, three-phase, 4-pole induction machine as shown in the figure. The dc machine is energized first and the machines rotate at 1600 rpm. Subsequently the induction machine is also connected to a 50Hz, three-phase source, the phase sequence being consistent with the direction of rotation. In steady state,
Answer : Option C
Explaination / Solution:
No Explaination.
Q10. 
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
