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JEE Main Physics Class 12 Moving Charges and Magnetism Part 1 Questions
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© examsnet.com
Question : 93
Total: 100
The magnetic field due to a current carrying circular loop of radius 3 cm at a point on the axis at a distance of 4 cm from the centre is 54 µT. What will be its value at the centre of loop?
[2004]
125 µT
150 µT
250 µT
75 µT
Validate
Solution:
The magnetic field at a point on the axis of a circular loop at a distance
x
from centre is,
B
=
µ
0
i
a
2
2
(
x
2
+
a
2
)
3
∕
2
Magnetic field at the centre of loop is
B
′
=
µ
0
i
2
a
∴
B
′
=
B
.
(
x
2
+
a
2
)
3
∕
2
a
3
Put
x
=
4
&
a
=
3
⇒
B
′
=
54
(
5
3
)
3
×
3
×
3
=
250
µ
T
© examsnet.com
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