Answer
The distance between the plates is 1500 km
Work Step by Step
We can find the distance between the plates:
$E~d = \Delta V$
$d = \frac{\Delta V}{E}$
$d = \frac{1.5~V}{1.0\times 10^{-6}~V/m}$
$d = 1.5\times 10^6~m$
$d = 1500~km$
The distance between the plates is 1500 km
