AP EAPCET 07-Jul-2022 Shift 2 Paper

Baxis=

µ0NIR2

2(x2+R2) 3 2

...(i)

Here, x=8‌cm,=8×10−2m
R=6‌cm=6×10−2m
and B=27µT=27×10−6T
Substituting these values in eq. (i), we get
27×10−6=

µ0‌NI×(6×10−2)2

2(8×10−2)2+(6×10−2)2]3∕2

=

µ0‌NI×(6×10−2)2

2[64×10−4+36×10−4]3∕2

⇒27×10−6=

µ‌NI×36×10−4

2×(10−2)3∕2

⇒27×10−6=

µ0‌NI×36×10−4

2×10−3

⇒µ0‌NI=

27×10−6×2×10−3

36×10−4

=

3

3

×10−5‌ units ‌ ...(ii)
Now, magnetic field at Centre, B‌centre =

µ0‌NI

2R

Substituting values in above expression from eq.(ii) we get,
B‌centre ‌=

‌ 3 2 ×10−5

2×6×10−2

=

1

8

×10−3T
=

1000

8

×10−6T
orB‌cenire ‌=125µT