A straight section PQ of a circuit lies along x-axis at x=-(a/2) to x=+(a/2) and carries a steady current (i), the magnetic field due to section PQ at a point x = + a will be

Question

A straight section PQ of a circuit lies along x-axis at x=-(a/2) to x=+(a/2) and carries a steady current (i), the magnetic field due to section PQ at a point x = + a will be (A) proportional to z (B) proportional to a2 (C) proportional to (1/a)  (D) equal to zero

Tardigrade Admin · Accepted Answer

From Biot Savarts law, magnetic field at point R due to a straight wire B=(μ 0/4π )(iΔ l sin θ /r2) but θ =0 ∴ B=0

Q. A straight section PQ of a circuit lies along x-axis at $x = - \frac{a}{2} t o x = + \frac{a}{2}$ and carries a steady current (i), the magnetic field due to section PQ at a point x = + a will be

proportional to z

proportional to a2

proportional to $\frac{1}{a}$

equal to zero

From Biot Savarts law, magnetic field at point R due to a straight wire $B = \frac{μ _{0}}{4 π} \frac{i Δ l s i n θ}{r ^{2}}$ but $θ = 0$ $∴$ $B = 0$

Q. A straight section PQ of a circuit lies along x-axis at x=−2a​tox=+2a​ and carries a steady current (i), the magnetic field due to section PQ at a point x = + a will be