邊個有最高電阻?

Assume that each piece of material is of the same dimensions and subject to the same voltage. Then by Ohm's Law,

Resistance = voltage/current
or resistance of the material is inversely proportional to the current that passing through it.

It is thus apparent that the resistance of material Y is highest, followed by material X, and material Z hs the least resistance.

Material Y can thus regarded as an insulator under the applied voltage.

根據歐姆定律，電流同電阻成反比，所以Y嘅電阻原理上係無限大，但電阻大小隨著施加電壓大小而改變。