Author Question: When calculating the Lorenz number L classically for electrical conductivity, you arrive at an ... (Read 50 times)

jon_i

  • Hero Member
  • *****
  • Posts: 549
When calculating the Lorenz number L classically for electrical conductivity, you arrive at an answer that is proven wrong experimentally. Which of the following statements is NOT true about the quantum mechanical contribution to the value of L?
  a. Quantum mechanics provides that thermal conductivity K is proportional to electrical conductivity over Avogadro's number, /NA.
 
b. Only electrons moving near the Fermi speed will be a factor in the conductivity.
  c.Quantum mechanics predicts a larger Lorenz number than classically calculated.
  d. The quantum Lorenz number depends on a different configuration of the same physical constants that the classical number depends on.

Question 2

Which of the following is NOT a general selection rule for the filling of electron shells?
 
a. For a particular n, the subshells fill in the order s, p, d, f, ...
  b.Shielding affects the ordering of energy levels as described by n and l.
  c. The orbital and spin angular momentum in each shell and subshell are restricted by Hund's rules.
  d. Electrons usually completely fill a subshell before starting another shell.
  e. For the s shell there are 2 electrons, for the p shell 6, for the d shell 10, and for the f shell 16.



fur

  • Sr. Member
  • ****
  • Posts: 309
Answer to Question 1

This statement is not true. The thermal conductivity K is indeed directly proportional to the electrical conductivity, but it is also directly proportional to the temperature T, K
a.

Answer to Question 2

e.
This statement is not true. The f subshells each take 14 electrons. Each l value subshell can take 2(2l + 1) electrons.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Everyone has one nostril that is larger than the other.

Did you know?

Since 1988, the CDC has reported a 99% reduction in bacterial meningitis caused by Haemophilus influenzae, due to the introduction of the vaccine against it.

Did you know?

Glaucoma is a leading cause of blindness. As of yet, there is no cure. Everyone is at risk, and there may be no warning signs. It is six to eight times more common in African Americans than in whites. The best and most effective way to detect glaucoma is to receive a dilated eye examination.

Did you know?

People with alcoholism are at a much greater risk of malnutrition than are other people and usually exhibit low levels of most vitamins (especially folic acid). This is because alcohol often takes the place of 50% of their daily intake of calories, with little nutritional value contained in it.

Did you know?

Drugs are in development that may cure asthma and hay fever once and for all. They target leukotrienes, which are known to cause tightening of the air passages in the lungs and increase mucus productions in nasal passages.

For a complete list of videos, visit our video library