Carbon exists as allotropes, which are different crystalline or molecular forms of the same substance. Graphite and diamond are allotropes of carbon. Diamond is a non-conductor whereas graphite is a good conductor because:
Correct answer: C. In graphite one of valence electron is free to move
- A. Graphite has a layered structure
- B. In graphite, all valence electrons are tetrahedrally bound
- C. In graphite one of valence electron is free to move
- D. Graphite is soft and greasy bound
Explanation
Graphite conducts electricity whereas diamond does not because in diamond the carbon atoms are bonded to other carbon atoms and all the valence electrons are bonded. whereas in graphite each carbon atom is only bonded to three other atoms. Therefore, there are delocalized (free) electrons in graphite due to 1 free valence electron in each carbon atom, which can move and carry a charge so graphite conducts electricity.
This question appeared on the UHS MDCAT 2011 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Electrical Properties of Solids
Electrical properties of solids depend on their band structure, charge carriers and conductivity. The topic compares conductors, insulators and semiconductors, relates resistivity to temperature, and covers intrinsic and extrinsic semiconductors, donor and acceptor impurities, electron and hole conduction, and the formation of p-type and n-type materials.
Practise Physics of Solids
320 free Physics of Solids MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 11 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Electrical Properties of Solids questions
The substances like germanium and silicon have:
Metallic conduction involves the relatively free movement of their _ throughout the metallic lattice.
Which of the following has the highest resistivity?
Which one of the following is the Boolean expression of the NAND gate?
Which one of the following is the truth table of the NAND gate?
If signal is applied to input of non-inverting amplifier through resistance of 100kohm, and the value of feedback resistance is 10kohm, the gain is: