¹¹The inverse square law applies to any form of radiation that spreads from a point-source. In any such scenario, the intensity of the radiation received by an object from the point-source diminishes with the square of the distance from that source, simply because the rest of the radiated energy misses that target and goes elsewhere in space. This is why the path loss formula begins with a −20 multiplier rather than −10 as is customary for decibel calculations: given the fact that the inverse square law tells us path loss is proportional to the square of distance (D²), there is a “hidden” second power in the formula. Following the logarithmic identity that exponents may be moved to the front of the logarithm function as multipliers, this means what would normally be a −10 multiplier turns into −20 and we are left with D rather than D² in the fraction.