A very long straight wire of radius r carries current I. Intensity of magnetic field B at a point, lying at a perpendicular distance 'a' from the axis is propto .

Question

A very long straight wire of radius r carries current I. Intensity of magnetic field B at a point, lying at a perpendicular distance 'a' from the axis is propto . (A) a2 (B) (1/a2) (C) (1/a) (D) a

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/e69a085502b3f28822ea33105b6ebf45-.png" /> B × 2 π a=μ0 × (I/2 π r2) × π a2 B=(μ0 I/2 π r2) × a B propto a

Q. A very long straight wire of radius $r$ carries current $I$ . Intensity of magnetic field $B$ at a point, lying at a perpendicular distance ' $a$ ' from the axis is $\propto$ ______.

$a^{2}$

$\frac{1}{a ^{2}}$

$\frac{1}{a}$

$a$

$B \times 2 πa = μ_{0} \times \frac{I}{2 π r ^{2}} \times π a^{2}$
$B = \frac{μ _{0} I}{2 π r ^{2}} \times a$
$B \propto a$

Q. A very long straight wire of radius r carries current I. Intensity of magnetic field B at a point, lying at a perpendicular distance 'a' from the axis is ∝ ______.

a2

a21​

a1​

a

B×2πa=μ0​×2πr2I​×πa2 B=2πr2μ0​I​×a B∝a

Q. A very long straight wire of radius $r$ carries current $I$ . Intensity of magnetic field $B$ at a point, lying at a perpendicular distance ' $a$ ' from the axis is $\propto$ ______.

$a^{2}$

$\frac{1}{a ^{2}}$

$\frac{1}{a}$

$a$

$B \times 2 πa = μ_{0} \times \frac{I}{2 π r ^{2}} \times π a^{2}$
$B = \frac{μ _{0} I}{2 π r ^{2}} \times a$
$B \propto a$