The insulation level of a $$400$$ kV, EHV overhead transmission line is decided on the basis of

The insulation resistance of a cable of length $$10$$ km is $$1$$ $$M\Omega $$. For a length of $$100$$ km of the same cable, the insulation resistance will be

The surge impedance of a $$400$$ km long overhead transmission line is $$400$$ $$\Omega $$. For a $$200$$ km length of the same line, the surge impedance will be

The rated load of an underground cable is always _______its natural load.