Question

For given current distribution, each infinite length wire produces magnetic field ${}^{\prime }{B}^{\prime }$ at origin then resultant magnetic field at origin ${}^{\prime }{O}^{\prime }$ is:-

• A. $4B$
• B. $\sqrt{2}B$
• C. $2\sqrt{2}B$
• D. $zero$

Answer 1

The correct option is C $2\sqrt{2}B$

Each infinite length wire produces magnetic field $=B$

origin then resultant magnetic field at $0$

$\sqrt{a^2+a^2}=\sqrt{{2a}^2}=a\sqrt{2}$

Now the field is $(\sqrt{2}+\sqrt{2})B=2\sqrt{2}B$.