According to the Band Theory, Why Is a Material Such

question 91

Multiple Choice

According to the band theory, why is a material such as diamond an insulator?

• A) All of the electrons are in the conduction band.
• B) All of the electrons are tied to nuclei.
• C) Very few electrons can make the transition over the large energy gap between the valence band and the conduction band.
• D) The bonds in diamond are too strong to allow atoms to move so no current flows.
• E) There are no electrons in the valence band.

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Definitions:

Separation Property

The property that portfolio choice can be separated into two independent tasks: (1) determination of the optimal risky portfolio, which is a purely technical problem, and (2) the personal choice of the best mix of the risky portfolio and the risk-free asset.

Risky Portfolio

An investment portfolio that contains assets with a higher degree of risk, potentially leading to higher returns or greater losses.

Complete Portfolio

The entire portfolio, including risky and risk-free assets.

Optimal Risky Portfolio

A combination of investments that yields the highest expected return for a specific level of risk.