From the point of view in an electrical way (currents and voltages) across the termial (black box with one terminal pair) you cannot imagine a any measurement to determine the content of the insite of the box. You can use non-electrical methods to detemine a Thévénin or Norton equivalent in case...
You can see at a glance that the result of 'studiot' is not correct. On the left side the dimension is 'meter', while on the right side the dimension is 'none'. The correct formula is:
S - L ≈ H*H/(2*S) or, preferable, S - L ≈ H*H/(2*L).