First slide

Magnetic field due to a straight current carrying wire

Question

A long straight non-conducting string carries a charge density of 40 μC/m. It is pulled along its length at a speed of 300 m/s. What is the magnetic field at a normal distance of 5 mm from the moving string?

Moderate

A

$4 .8 \times 10^{- 7} tesla$
B

$3.2 \times 10^{- 7} tesla$
C

$2.5 \times 10^{- 7} tesla$
D

$5 \times 10^{- 7} tesla$

Solution

The moving string behaves like a current, therefore
$\begin{array}{l} i = (40 \times 10^{- 6} C / m) (300 m / s) \\ = 1 .2 \times 10^{- 2} A \end{array}$
$\begin{array}{l} Then B = \frac{μ_{0} i}{2 πr} = \frac{2 \times 10^{- 7} \times 1 .2 \times 10^{- 2}}{0 .005} \\ = 4 .8 \times 10^{- 7} T \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App