Question

Two large metal sheets carrying electric current along their surface. If current per unit length of the sheet is $\lambda$. The magnetic field at a point $\text{P}$ on the same side of the sheets is

• A. ${\mu }_0\lambda$
• B. $\frac{{\mu }_0\lambda }{2}$
• C. cannot be determined as the distances of the point from sheets are not given.
• D. is independent of the distance of the point from the sheets.

Answer 1

Answer: (A), (D)

The correct options are
A ${\mu }_0\lambda$
D is independent of the distance of the point from the sheets.


The magnetic field outside the infinite sheet is constant, independent of the distance from the sheet.

So, the magnetic field due to large metal sheets is,

$B=\frac{{\mu }_0\lambda }{2}$

$\Rightarrow B_1=\frac{{\mu }_o\lambda }{2}$

$\Rightarrow B_2=\frac{{\mu }_o\lambda }{2}$

The resultant field at point $\text{P}$ is,

$B_{net}=B_1+B_2$

$\therefore B_{net}=\frac{{\mu }_0\lambda }{2}+\frac{{\mu }_0\lambda }{2}={\mu }_0\lambda$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(A\right)$ and $\left(D\right)$ are the correct answers.