A parallel plate capacitor consisting of two circular plates of radius 10 cm is being charged by a constant current of 0.15 A . If the rate of change of potential difference between the plates is $7 \times 10^{8} \mathrm{~V} / \mathrm{s}$ then the integer value of the distance between the parallel plates is (Take, $\left.\epsilon_{0}=9 \times 10^{-12} \frac{\mathrm{~F}}{\mathrm{~m}}, \pi=\frac{22}{7}\right)$ $\_\_\_\_$ $\mu \mathrm{m}$.