A current signal is expressed as i(t)= Im sin(2πft). Now derive the RMS expression of the given voltage signal.
Answers
Answer:
search-icon-header
Search for questions & chapters
search-icon-image
Class 12
>>Physics
>>Alternating Current
>>Introduction to Phasors and Problems on it
>>A device X is connected acr...
Question
Bookmark
A device X is connected across an ac source of voltage V=V
0
sinωt. The current through X is given as I=I
0
sin(ωt+
2
π
).
(a) Identify the device X and write the expression for its reactance.
(b) Draw graphs showing variation of voltage and current with time over one cycle of ac, for X.
(c) How does the reactance of the device X vary with frequency of the ac? Show this variation graphically.
(d) Draw the phasor diagram for the device X.
Medium
Solution
verified
Verified by Toppr
(a) Here V=V
0
sinωt
I=I
0
sin(ωt+
2
π
)
Since current is leading the voltage by
2
π
, hence the circuit must be capacitive and the element "X" must be a capacitor.
Its reactance is given by X
c
=
ωC
1
(b) Graph of voltage and current w.r.t time in fig(b)
(c) Graph showing the variation of X
C
with frequency f in fig(c)
Since X
c
=
2πfC
1
X
c
∝
f
1
Hence, reactance is inversely proportional to the frequency.