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Tardigrade
Question
Physics
The current density in a cylindrical wire of radius r =4.0 mm is 1.0 × 106 A / m 2. The current through the outer portion of the wire between radial distances r / 2 and r is x π A; where x is
Q. The current density in a cylindrical wire of radius
r
=
4.0
mm
is
1.0
×
1
0
6
A
/
m
2
. The current through the outer portion of the wire between radial distances
r
/2
and
r
is
x
π
A
; where
x
is ______
957
158
JEE Main
JEE Main 2022
Current Electricity
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Answer:
12
Solution:
I
=
∫
Jd
A
=
∫
1
0
6
×
2
π
x
d
x
=
1
0
6
×
2
π
⋅
x
2
x
2
]
2
r
r
=
π
×
1
0
6
[
r
2
−
4
r
2
]
=
12
π
x
=
12