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Grade 11Magnetism


Infinite number of straight wires each carrying current I are equally placed as shown in the figure. Adjacent
wires have current in opposite direction. Net magnetic field at point P is

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Profile image of ARYAN RAJ
6 Years agoGrade 11
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2 Answers

Profile image of Vikas TU
6 Years ago
Hiii 
The magnetic field from a straight finite length wire is :
mwe * I (sinQ1 + sinQ2 )/4*pie*d
 
d = a cos 30 = a*sqrt(3)/2
 
The magnetic field at a point P from the wire are written as 
 
 
ln (1+x) = x-x^2/2 + x^3/3 -x^4/4
consider x = 1 
so it will become log2
So, A would be the correct ans.
Profile image of Khimraj
6 Years ago
Magnetic field from a straight finite length wire is  
d= perpendicular distance of point from wire
I = Current, are angle of elevation from the point to top and bottom of wire
 
 
So the magnetic field at point P from the wires are given as 
 
 
 
 

If we consider x=1 then we get 
Therefore the magnetic field at point P is equal to