If the slope of the characteristics curve of a vacuum tube diode corresponding to some point is <img alt="\mathrm{10^{-3}mAV^{-1}}" src="https://entrancecorner.oncodecogs.com/gif.latex?%5Cmathrm%7B
If the slope of the characteristics curve of a vacuum tube diode corresponding to some point is , then the plate resistance of diode and its nature are respectively