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Electronics and Communication Engineering - Signals and Systems

Exercise : Signals and Systems - Section 2
31.
A voltage wave v = 10 + 20 sin ωt + 7.5 sin 3 ω(t) is applied to a series combination of two elements. The current is i = 5 sin (ωt + 20°) + 1.5 sin (3ωt + 10°). The elements are
R and C
R and L
L and C
both inductances
Answer: Option
Explanation:

DC component is absent in current and current is leading the voltage. Hence R and C.

32.
If F(t) = δ(t - a), F(s)=
0
1
e-as
eas
Answer: Option
Explanation:

It is an impulse originating at t = a.

33.
The property is not valid for basic singularity function is
it is even signal
convolution of any arbitary function x(t) and an impulse is the original function itself
the sum of two impulses at same location is the impulse with the strength equal to the summation of individual strengths.
none of these.
Answer: Option
Explanation:

Singularity function is discontinuous at origin like ∪(t), δ(t).

34.
Magnitude Plot of a Composite signal x(t) = e2jt + e3jt is
half wave rectified sinusoidal
full wave rectified sinusoidal
exponentially increasing sinusoidal
exponentially decreasing sinusoidal
Answer: Option
Explanation:

x(t) = e2jt

⇒ x(t) = 2ej2.5t cos(0.5t)

The magnitude |x(t)| = 2 cos |0.5t| which is a full rectified wave.

35.
The final value of is
∞
2
1
zero
Answer: Option
Explanation:

.

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