(Hint: First find the selfinductance.)
The energy stored in a solenoid is given by
E
=
1
2
L I
2
,
where
L
is the inductance of the solenoid.
At what frequency does the light bulb glow
most brightly?
gilbert (amg3448) – HW07 – tsoi – (57210)
8
2.
the frequency
ω
=
1
√
LC
3.
both very low frequencies or very high
frequencies
correct
di
ff
erence output of 106 V.
Find the
rms
potential di
ff
erence output.
5.
very low frequencies
An AC generator has a maximum potential
di
ff
erence output of 106 V.
Find the
rms
potential di
ff
erence output.
The
rms
voltage is
Find the
rms
current in the circuit when the
generator is connected to a 53
Ω
resistor.
Determine the magnitude of the current in
the capacitor at
t
= 0
.
00895 s, assuming that
at
t
= 0, the energy stored in the capacitor is
zero.
020 (part 1 of 2) 10.0 points
Explanation:
gilbert (amg3448) – HW07 – tsoi – (57210)
9
Let :
V
rms
= 69
.
4 V
,
C
= 1
.
5 mF = 0
.
0015 F
,
f
= 20 Hz
,
and
t
= 0
.
00895 s
.
The capacitive reactance is
X
C
=
1
ω
C
=
1
2
π
f C
.
The maximum current is
I
max
=
V
max
X
C
=
√
2
V
rms
X
C
=
√
2 (2
π
f C
)
V
rms
.
Because the current leads the voltage across a
capacitor by 90
◦
, at time
t
,
I
=
I
max
sin (
ω
t
+ 90
◦
)
= 2
√
2
π
f C V
rms
sin (2
π
f t
+ 90
◦
)
= 2
√
2
π
(20 Hz) (0
.
0015 F) (69
.
4 V)
×
sin [2
π
(20 Hz)(0
.
00895 s) + 90
◦
]
= 7
.
98201 A
,
so

I

=
7
.
98201 A
.
keywords:
023
10.0 points
An inductor has a 68
.
4
Ω
reactance at 57
.
8 Hz.
What will be the peak current if this in
ductor is connected to a 26 Hz source that
produces a 159 V
rms
voltage?