Question

Consider a circular coil of wire carrying current $I$, forming a magnetic dipole. The magnetic flux through an infinite plane that contains the circular coil and excluding the circular coil area is given by ${\varphi }_i$. The magnetic flux through the area of the circular coil area is given by ${\varphi }_0$. Which of the following option is correct?

• A. ${\varphi }_i=-{\varphi }_o$
• B. ${\varphi }_i>{\varphi }_o$
• C. ${\varphi }_i<{\varphi }_o$
• D. ${\varphi }_i={\varphi }_o$

Answer 1

The correct option is A ${\varphi }_i=-{\varphi }_o$


As magnetic field line of ring will form close loop therefore all outgoing from circular hole passing through the infinite plate.

$\therefore {\varphi }_i=-{\varphi }_0$
(because the magnetic field lines going inside is equal to the magnetic field lines coming out.)