Question

If $i_1$, and $i_2$ currents are flowing in two wires mutually perpendicular to each other and placed very near, then find the equation of locus of the points of zero magnetic field.

• A. Straight line
• B. Circle
• C. Para bola
• D. Ellipse

Answer 1

The correct option is A Straight line

Given: Magnetic field of two wires is $i_1,i_2$

Solution: When two wires are placed perpendicular then magnetic field can be zero in two two quadrants i.e.1 &3

In first quadrant :

Direction of magnetic field due to RS wire is $\otimes$

Direction of magnetic field due to PQ wire is $\odot$

In third quadrant :

Direction of magnetic field due to PQ wire is $\otimes$

Direction of magnetic field due to RS wire is $\odot$

We know that the value of magnetic field is same so if we join the points then we get straight line.

Hence the correct option is A