9.3.13. A cylindrical ferromagnetic column with narrow cavities was placed in a long solenoid with a current of $0.5 A$. The number of turns per $1 cm$ of the length of the solenoid is $10$, the magnetic permeability of the ferromagnet is $600$. Determine the magnetic field induction in the longitudinal and transverse cavities (at points $A$ and $B$).
Solution
Inside the longitudinal section, the field corresponds to the field of the solenoid, inside the transverse section it is amplified in accordance with the magnetic permeability: $$B_{||}=\mu_0 I n \approx 6,28 \cdot 10^{-4} Т$$ $$B_{\perp}=\mu \mu_0 I n \approx 0,377 Т$$
Answer
$$B_{||}=\mu_0 I n \approx 6,28 \cdot 10^{-4} Т$$ $$B_{\perp}=\mu \mu_0 I n \approx 0,377 Т$$
