1
$\begingroup$

Two bar magnets with area $a$, in axis, at a distance of $d$ ($d$ is much biffer than $a$) attract each other with a force of $F$.
What is the force between two infinite surfaces made of the same material, at the distance of $d$ per $a$?

My work:

According to Wikipedia in those circumstances the force between the surfaces is calculated by:

$F = \frac{B^2A}{2μ}$

The only variable I'm missing is B.
Now, the force between two poles is:

$F = \frac{μq_1q_2}{4πd^2}$

Sadly I have no idea how to use the calculated $q_1\cdot q_2$ to get $B$.

What is the missing step?

$\endgroup$
0
$\begingroup$

That is a much complex approach to solving the problem. What I instead suggest is to consider the magnetic strength ($q_m$) which is the charge the hypothetical monopole would have. Considering it as an electrostatic system solve it using the equations of electrostatics by replacing 1/$\epsilon_0$ by $\mu_0$.

B is nothing but an analogue to E for a dipole ($q_m$ and $-q_m$).

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.