A solenoid has a core made of material with relative permeability 400. The magnetic field produced in the interior of solenoid is 1.0 T. The magnetic…

A solenoid has a core made of material with relative permeability $\displaystyle 400$ . The magnetic field produced in the interior of solenoid is $\displaystyle 1.0$ T. The magnetic intensity in SI units is $\displaystyle \alpha \times 10^5$. The value of $\displaystyle \alpha$ is $\displaystyle \_\_\_\_$. (Free space permeability $\displaystyle \mu_0=4 \pi \times 10^{-7}$ SI units.)