Electrical Engineering - Online Test
Q1. Let x1(t) ↔ X1(ω) and x2(t) ↔ X2(ω) be two signals whose Fourier Transforms are as shown in the figure below. In the figure, h(t) = e-2|t| denotes the impulse response.
For the system shown above, the minimum sampling rate required to sample y(t), so that y(t) can be uniquely reconstructed from its samples, is
Answer : Option B
Explaination / Solution:
Q2. Consider a linear time invariant system x = Ax, with initial condition x(0) at t = 0. Suppose α and β are eigenvectors of (2 x 2) matrix A corresponding to distinct eigenvalues λ1 and λ2 respectively.
Then the response x(t) of the system due to initial condition x(0) = α is
Answer : Option A
Explaination / Solution:
Q3. The bus admittance matrix for a power system network is 
pu
puThere is a transmission line, connected between buses 1 and 3, which is represented by the
circuit shown in figure.
If this transmission line is removed from service, What is the modified bus admittance matrix?
Answer : Option C
Explaination / Solution:
Q4. The divergence of the vector field 
Answer : Option D
Explaination / Solution:
Given, the vector field
Q5. The signal 
is
is
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. A balanced three-phase voltage is applied to a star-connected induction motor, the phase to
neutral voltage being V. The stator resistance, rotor resistance referred to the stator, stator
leakage reactance, rotor leakage reactance referred to the stator, and the magnetizing
reactance are denoted by rs , rr , xs , xr and Xm, respectively. The magnitude of starting current
of the motor is given by
Answer : Option A
Explaination / Solution:
No Explaination.
Q7.
The ratio of the mobility to the diffusion coefficient in a semiconductor has the units
Answer : Option A
Explaination / Solution:
Q8. The increasing order of speed of data access for the following devices is
i. Cache Memory
ii. CDROM
iii. Dynamic RAM
iv. Processor Registers
v. Magnetic Tape
Answer : Option B
Explaination / Solution:
No Explaination.
Q9. The electron and hole concentrations in an intrinsic semiconductor are ni per cm3 at 300 K. Now, if acceptor impurities are introduced with a concentration
of NA per cm3
(where NA >> ni , the electron concentration per cm3 at 300 K
will be
Answer : Option D
Explaination / Solution:
As per mass action law
np = ni
If acceptor impurities are introduces
Q10. 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 D
Explaination / Solution:
