Examsnet
Unconfined exams practice
Home
Exams
Banking Entrance Exams
CUET Exam Papers
Defence Exams
Engineering Exams
Finance Entrance Exams
GATE Exam Practice
Insurance Exams
International Exams
JEE Exams
LAW Entrance Exams
MBA Entrance Exams
MCA Entrance Exams
Medical Entrance Exams
Other Entrance Exams
Police Exams
Public Service Commission (PSC)
RRB Entrance Exams
SSC Exams
State Govt Exams
Subjectwise Practice
Teacher Exams
SET Exams(State Eligibility Test)
UPSC Entrance Exams
Aptitude
Algebra and Higher Mathematics
Arithmetic
Commercial Mathematics
Data Based Mathematics
Geometry and Mensuration
Number System and Numeracy
Problem Solving
Board Exams
Andhra
Bihar
CBSE
Gujarat
Haryana
ICSE
Jammu and Kashmir
Karnataka
Kerala
Madhya Pradesh
Maharashtra
Odisha
Tamil Nadu
Telangana
Uttar Pradesh
English
Competitive English
Certifications
Technical
Cloud Tech Certifications
Security Tech Certifications
Management
IT Infrastructure
More
About
Careers
Contact Us
Our Apps
Privacy
Test Index
JEE Main 31-Aug-2021 Shift 2 Solved Paper
Show Para
Hide Para
Share question:
© examsnet.com
Question : 2
Total: 90
A current of
1.5
A
is flowing through a triangle, of side
9
cm
each. The magnetic field at the centroid of the triangle is
(Assume that, the current is flowing in the clockwise direction.)
[31 Aug 2021 Shift 2]
3
×
10
−
7
T
, outside the plane of triangle
2
√
3
×
10
−
7
T
, outside the plane of triangle
2
√
3
×
10
−
5
T
, inside the plane of triangle
3
×
10
−
5
T
, inside the plane of triangle
Validate
Solution:
Given, electric current, I = 1.5 A
Side of triangle,
l
=
9
cm
=
9
×
10
−
2
m
Let OD = OE = OF = r
AD
=
l
2
In
Δ
AOD
,
OD
AD
=
tan
30
°
OD
=
AD
tan
30
°
r
=
OD
=
l
2
×
1
√
3
=
l
2
√
3
Magnetic field due to AB at O,
B
1
=
µ
0
I
4
π
r
[
sin
60
°
+
sin
60
°
]
=
µ
0
I
4
π
r
×
2
√
3
2
⇒
B
1
=
µ
0
d
√
3
4
π
r
(perpendicular inward)
Now, total magnetic field at O due to all sides,
B
=
3
B
1
=
µ
0
4
π
r
3
√
3
By substituting the values, we get
B
=
10
−
7
×
1.5
×
3
√
3
×
2
√
3
9
×
10
−
2
=
3
×
10
−
5
T
(inside the plane of triangle)
© examsnet.com
Go to Question:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
Prev Question
Next Question