Physics - Magnetism Question with Solution | TestHub

PhysicsMagnetismBiot-savart's & Ampere's Circuital lawEasy2 minPYQ_2020
PhysicsEasysingle choice

Two long parallel wires carry currentsi1 and i2such thati1>i2.When the currents are in the same direction, the magnetic field at a point midway between the wires is6×10-6 T.If the direction ofi2is reversed, the field becomes3×10-5 T.The ratioi1i2is

Options:

Answer:
C
Solution:

When the currents are in the same direction then the magnetic field

      B=μ04π×2d i1-i2

    6×10-6= μ04π×2d i1-i2           (i)

When the currents are in the reversed direction then the magnetic field

                      B2=μ04π×2d i1-(-i2) 

or    B2=μ04π×2d i1+i2 

or  3×10-5=μ04π×2di1+i2    (ii)

Dividing Eq. (i) by Eq. (ii)

              i1-i2i1+i2=6×10-63×10-5

or           i1-i2i1+i2=210

or  5i1-5i2=i1+i2

or             4i1=6i2

                      i1i2=64

                      i1i2=32

Subject:PhysicsTopic:MagnetismSubtopic:Biot-savart's & Ampere's Circuital law
2mℹ️ Source: PYQ_2020

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