public static function getMassCharge($mass, $charge)
    {
        if (! is_float($mass)) {
            throw new \InvalidArgumentException('Argument 1 must be of type float. Value is of type ' . gettype($mass));
        }

        if (! is_int($charge)) {
            throw new \InvalidArgumentException('Argument 2 must be of type int. Value is of type ' . gettype($charge));
        }

        if ($charge == 0) {
            return $mass;
        }

        return ($mass + ($charge * PhysicalConstants::PROTON_MASS)) / $charge;
    }