固体物理、核物理学および粒子模型
導入済み| English | 意味 |
|---|---|
| band gap/bænd ɡæp/ | バンドギャップ |
| half-life/hɑːf laɪf/ | 半減期 |
A decision before an answer
- A semiconductor’s conductivity depends on available states and carriers, not merely on the number of electrons in the material.
- Your goal: Use band and carrier descriptions.
Read the relationship
- Filled bands cannot carry ordinary current without accessible nearby states. Metals have partially filled or overlapping bands; semiconductors have a small band gap. Donor and acceptor doping change carrier populations.
- Apply radioactive decay and binding-energy ideas.
After two half-lives, the remaining fraction is:
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
Two successive halvings give one quarter.
Use the defining rule
- Fermi–Dirac occupancy is 1/[exp((E−μ)/(kT))+1]. At zero temperature it becomes a step at the Fermi energy; thermal broadening does not make every state half occupied.
- Check conservation laws in particle reactions.
Donor doping commonly supplies:
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
Donor levels facilitate electron excitation into conducting states.
Check the conditions
- Radioactive populations obey N=N0e^(−λt), activity λN and half-life ln2/λ. Binding energy comes from a mass deficit multiplied by c²; compare binding energy per nucleon when discussing stability.
- Check conservation laws in particle reactions.
After three half-lives, N/N0=(1/2)^3=1/8, so activity is also one eighth if λ is unchanged. A mass defect of 0.010 u corresponds to about 9.315 MeV using 1 u c²=931.5 MeV.
After four half-lives, one part in ____ remains.
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
2^4=16.
Apply the task format
- Nuclear and particle processes must conserve charge, energy, momentum and the applicable quantum numbers. Beta decay includes a neutrino or antineutrino; a two-body electron-only story cannot explain its continuous energy spectrum.
- Check conservation laws in particle reactions.
Activity and surviving population both decay, but their units differ: activity is transitions per second.
このケースに当てはまる答えはどれか？
バンドとキャリアの記述を用いる
Charge conservation alone is sufficient to validate any particle reaction.
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
Energy, momentum and other applicable conservation laws also matter.
Keep the distinctions
- band gap 带隙 — An energy interval with no allowed bulk electronic states in the band model.
- half-life 半衰期 — Time for a radioactive population to halve.
- Use band and carrier descriptions.
- Apply radioactive decay and binding-energy ideas.
- Check conservation laws in particle reactions.
Match each term with its precise meaning in this lesson.
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
Keep the distinctions stated in the teaching example.
Put this lesson’s reasoning or event sequence in order.
難易度 3/5 · 200 コイン + 今日初回完了時に小ボーナス付与
The order follows the stated process; check each stage before the next.