Question

The magnetic field at point P is zero. Findthe distance, r2, from P to the second wire,1₂.I₁ = 4.32 A P------0.831 m1₂ = 7.50 Ar2r₂ = [?] m

Answer 1

The formula for calculating the magnetic field is

B = μo[(I1/2πR1) - (I2/2πR2)]

B = μo/2π[(I1/R1) - (I2/R2)]

where

B is the magnetic field

μo is the permeability of free space

From the information given,

B = 0

I1 = 4.32

R1 = 0.831

I2 = 7.5

R2 = ?

μo = 4π x 10^-7 Tm/A

Thus,

0 = 4π x 10^-7/2π[(4.32/0.831) - (7.5/R2)]

0 = 4 x 10^-7/2[(4.32/0.831) - (7.5/R2)]

0 = 4 x 10^-7/2(4.32/0.831) - 4 x 10^-7/2(7.5/R2)]

4 x 10^-7/2(7.5/R2)] = 4 x 10^-7/2(4.32/0.831)

7.5/R2 = 4.32/0.831

By cross multiplying,

4.32R2 = 7.5 x 0.831

R2 = (7.5 x 0.831)/4.32

R2 = 1.443 m