Question

plssss solve itttt...........

Answer 1

The magnetic field lines are circular around each conductor. They are on the surface of cylinders with the conductor being the axis.

Magnetic field due to current I at a point P:
B = μ i/ (2 pi d)
I = current, d = distance of point P from the conductor.
Direction is tangential to the circle of radius d. It can be found using right hand thumb rule.

Except for points between the two conductors, the magnetic fields due to both will be in the same direction. So for points < 2cm or for points > 6cm, resultant field is not zero.

Let the point P, at which field is 0, be at d cm distance from left conductor. So it's 4-d cm from the rightside conductor.

B = μ/(2 pi) * [ 1 / d - 3 /(4 - d) ] = 0
So 4 - d = 3d
d = 1 cm.

Null field Point is 3 cm mark.