Which of the listed substances are electrical non-conductors?
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Answer: D. All of the above
Explanation
Non-metal solids except carbon lack free electrons needed to establish a continuous electrical conduction current. Air and most other gases act as excellent electrical insulators under normal atmospheric temperature and pressure conditions. Pure water and general liquids, excluding liquid metals like mercury, lack mobile charge carriers and do not conduct electricity well. Electrical insulators are materials that impede the free flow of electrical charge through their internal atomic structure. Carbon in the form of graphite contains delocalized electrons, making it a notable non-metal exception that conducts electricity. Dielectric strength measures the maximum electric field an insulating material can withstand without experiencing electrical breakdown.
Non-metal solids except carbon accurately describe insulators, but other valid categories are also included in the question. Air and most other gases correctly represent gaseous insulating mediums, making single category selection incomplete. Pure water and liquids in general except mercury correctly identify liquid insulators, confirming all listed options are right.
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- Engineering
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- Electrical Engineering
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