Water is running into an underground right circular conical reservoir, which is $10 \mathrm{m}$ deep and radius of its base is $5 \mathrm{m}.$ If the rate of change in the volume of water in the reservoir is $\frac{3}{2}\frac{\pi {\mathrm{m}}^3}{\min }$, then the rate (in $\frac{\mathrm{m}}{\min }$) at which water rises in it, when the water level is $4 \mathrm{m}$, is