Electrical Engineering - Online Test
Q1. The time domain behavior of an RL circuit is represented by 
For an initial current of
For an initial current ofFor an initial current of 
the steady state value of the current is given by
the steady state value of the current is given by
Answer : Option A
Explaination / Solution:
Steady state all transient effect die out and inductor act as short circuits and forced response acts only. It doesn’t depend on initial current state. From the given time domain behavior we get that circuit has only R and L in series with v0 Thus at steady state 
Q2. The input and output of a continuous time system are respectively denoted by x(t) and y(t). Which of the following descriptions corresponds to a causal system ?
Answer : Option C
Explaination / Solution:
The output of causal system depends only on present and past states only.
In option (A) y(0) depends on x(- 2) and x(4).
In option (B) y(0) depends on x(1).
In option (C) y(0) depends on x(- 1).
In option (D) y(0) depends on x(5).
Thus only in option (C) the value of y(t) at t = 0 depends on x(- 1) past value.
In all other option present value depends on future value.
Q3. Drift current in the semiconductors depends upon
Answer : Option C
Explaination / Solution:
No Explaination.
Q4. 
For the output F to be 1 in the logic circuit shown, the input combination should be
Answer : Option C
Explaination / Solution:
Q5. The trace and determinant of a 2 × 2 matrix are known to be –2 and –35 respectively. It’s Eigenvalues are
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. In the circuit shown, vC is 0 volts at t = 0 sec. For t > 0, the capacitor current iC(t), where t is in seconds is given by
Answer : Option A
Explaination / Solution:
Q7.
The longitudinal component of the magnetic field inside an air-filled rectangular waveguide made of a perfect electric conductor is given by the following expression 
The cross-sectional dimensions of the waveguide are given as a = 0.08 m and b = 0.033 m. The mode of propagation inside the waveguide is
The cross-sectional dimensions of the waveguide are given as a = 0.08 m and b = 0.033 m. The mode of propagation inside the waveguide is
Answer : Option C
Explaination / Solution:
We have the expression,
and the cross sectional dimension is
a = 0.08 m, b = 0.033m
Now, we compare the equation for TEm,n mode whose Hz is given as
Hence, given mode is TE21 mode
Q8. The impulse response h(t) of a linear time invariant continuous time system is
described by 
where u(-t) denotes the unit
step function, and α and β are real constants. This system is stable if
where u(-t) denotes the unit
step function, and α and β are real constants. This system is stable if
Answer : Option D
Explaination / Solution:
This system is stable only when bounded input has bounded output For stability αt < 0 for t > 0 that implies α < 0 and βt > 0 for t > 0 that implies β > 0. Thus, α is negative and β is positive.
Q9. The pole-zero given below correspond to a
Answer : Option C
Explaination / Solution:
Q10. A Zener diode, when used in voltage stabilization circuits, is biased in
Answer : Option B
Explaination / Solution:
Zener diode operates in reverse breakdown region.
