A transmission wire positioned 8 m above a road carries a current of 100 A . Determine the magnetic field B at a point on the road.

Correct answer: C. 2.5 × 10^ -6 T The magnetic field due to a long straight wire at a perpendicular distance r is given by B = (μ_0 I)/(2π r) . Given I = 100 A and r = 8 m . Substituting the values: B = 4π × 10^ -7 × 100 2π × 8 B = 2 × 10^ -5 8 B = 0.25 × 10^ -5 T B = 2.5 × 10^ -6 T

Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Magnetic Field due to a Current

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Magnetic Field due to a Current

A transmission wire positioned 8 m above a road carries a current...

A transmission wire positioned

8 \text{ m}

above a road carries a current of

100 \text{ A}

. Determine the magnetic field

B

at a point on the road.

Options

A $1.25 \times 10^{-6} \text{ T}$
B $5.0 \times 10^{-6} \text{ T}$
C $2.5 \times 10^{-6} \text{ T}$
D $2.5 \times 10^{-5} \text{ T}$

Correct answer

C. $2.5 \times 10^{-6} \text{ T}$

Step-by-step solution

The magnetic field due to a long straight wire at a perpendicular distance

r

is given by

B = \dfrac{\mu_0 I}{2\pi r}

.

Given

I = 100 \text{ A}

and

r = 8 \text{ m}

.

Substituting the values:

B = \dfrac{4\pi \times 10^{-7} \times 100}{2\pi \times 8}

B = \dfrac{2 \times 10^{-5}}{8}

B = 0.25 \times 10^{-5} \text{ T}

B = 2.5 \times 10^{-6} \text{ T}

Practice Magnetic Field due to a Current on Quantrex Academy →

More from Magnetic Field due to a Current