A coil having a resistance of 15 ohms and an inductance of 10 henry is connected to 90 volts supply.
· The approximate value of current after 2 seconds is. (Given e-3 = 0.05.)
Answers
Answered by
1
Answer:
Given that,
L = 10 H
R = 2 ohm
V = 10 volt
Now, the maximum current is
i
0
=
R
V
i
0
=
2
10
i
0
=5A
The maximum energy is
E
0
=
2
1
Li
0
2
E
0
=
2
1
×10×5×5
E
0
=125J
Now, the magnetic energy
E=
4
E
0
E=
4
125
J
Now,
E=
2
1
Li
2
4
125
=
2
1
Li
2
2×10
125
=i
2
i
2
=
2
25
i=
2
5
i=2.5A
Now, the time taken to rise current from 0 - 2.5A.
We know that, the instantaneous current during its growth in an L-R circuit.
i=i
0
(1−e
−
L
Rt
)
2.5=5(1−e
−
L
Rt
)
e
L
−Rt
=0.5
L
−Rt
=ln(0.5)
L
Rt
=0.693
t=
2
6.93
t=3.46
t=3.5sec
Hence, the magnetic energy will be increases to
4
1
of the maximum value at 3.5 sec.
Hope it helps you....!!!
Answered by
0
Step-by-step explanation:
The approximate value of current after 2 seconds is 5.7 amperes
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