核反应的 Q 值与质量亏损如何由 E=mc² 联系？
How does E=mc² link Q-value and mass defect in nuclear reactions?
反应前后静止质量之差 Δm 转化为释放的能量 Q=Δm c²；若产物总质量小于反应物则放能（裂变/聚变），反之吸能。这正是质量亏损的能量体现。
The rest-mass difference Δm between products and reactants releases Q=Δm c²; lighter products mean energy is emitted (fission/fusion), heavier means absorbed—the mass defect as energy.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #质量亏损 #Q值
核聚变和核裂变有什么不同？
What is the difference between fusion and fission?
裂变是把重核拆开，聚变是把轻核（如氢）合并成较重的核；聚变释放更多能量且更清洁，但需要在极高温度下才能进行，如太阳内部。
Fission splits heavy nuclei; fusion joins light ones like hydrogen. Fusion releases more energy and is cleaner but needs extreme temperatures, as in the Sun.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03 · 2 条独立证据
来源 · Source
Bethe，《恒星中的能量产生》，Physical Review 55 (1939)
Bethe, 'Energy Production in Stars', Physical Review 55 (1939)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1103/PhysRev.55.434：Energy Production in · 核验依据 2 CROSSREF 标识 10.1126/science.88.2296.6.u：Energy Productio
#核聚变 #核裂变 #太阳
核裂变是怎么释放能量的？
How does nuclear fission release energy?
重核（如铀）被中子击中后分裂成两个较轻的核，质量总和略减，亏损的质量按 E=mc² 变成巨大能量释放出来。
A heavy nucleus like uranium splits after absorbing a neutron; the fragments weigh slightly less than the original, and that missing mass becomes large energy via E=mc².
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Hahn 与 Strassmann，《论铀被中子轰击后产生的碱土金属》，Naturwissenschaften 27 (1939)
Hahn & Strassmann, 'Uber den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle', Naturwissenschaften 27 (1939)
#核裂变 #铀 #能量
核电站和原子弹释放能量的方式有何本质区别？
What is the key difference between how a nuclear plant and a bomb release energy?
两者都用裂变，但核电站靠控制棒缓慢、可控地链式反应持续放热发电；原子弹去掉控制让反应在瞬间失控、剧烈爆炸。
Both use fission, but a reactor uses control rods to keep a slow, steady chain reaction for power, while a bomb removes controls so the reaction runs away explosively in an instant.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Lamarsh 与 Baratta，《核工程导论》（第3版）
Lamarsh & Baratta, 'Introduction to Nuclear Engineering' (3rd ed.)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL5901582W：Introduction to nuclear
#核电站 #链式反应 #控制
核反应堆里为什么要放“减速剂”（如重水、石墨），把快中子慢化下来才能维持链式反应？
Why does a nuclear reactor need a 'moderator' like heavy water or graphite to slow neutrons before a chain reaction can sustain?
铀-235 更容易俘获慢（热）中子而非快中子。减速剂由轻核组成，中子与其碰撞会损失动能、降速到热区，从而大幅提高被 U-235 吸收并引发下一次裂变的概率。没有慢化，多数快中子会直接逃逸，链式反应无法维持。
Uranium-235 captures slow (thermal) neutrons far more readily than fast ones. A moderator made of light nuclei slows neutrons through collisions, bringing them into the thermal range where U-235 capture and the next fission become much more likely. Without moderation most fast neutrons escape and the chain reaction dies.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 2 条独立证据
来源 · Source
K. S. Krane,《Introductory Nuclear Physics》(Wiley,1987),第13章(核裂变)
K. S. Krane, 'Introductory Nuclear Physics' (Wiley, 1987), Ch.13 (Nuclear Fission)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780471805533 (1987) · 核验依据 2 ISBN 9780471805533 (1988)
#减速剂 #热中子 #链式反应
为什么像铀-238这样的重核会发生自发裂变，而轻得多的核几乎从不会这样？
Why do heavy nuclei like uranium-238 undergo spontaneous fission while much lighter nuclei essentially never do?
按液滴模型，核的库仑排斥能大致按 Z²/A^(1/3) 增长，而抑制形变的表面能只按 A^(2/3) 增长，所以核越重、排斥越占优势，裂变势垒越低越薄。铀-238 的势垒已低到能被量子隧穿，于是可以自发裂变，但概率极小——自发裂变半衰期约 10¹⁶ 年，远长于它的 α 衰变寿命。轻核的势垒又高又厚，自发裂变实际上观测不到。
In the liquid-drop model the Coulomb repulsion energy scales roughly as Z²/A^(1/3) while the surface energy that resists deformation grows only as A^(2/3), so the heavier the nucleus the more repulsion dominates and the lower and thinner the fission barrier becomes. For uranium-238 the barrier is low enough to be tunnelled through, so spontaneous fission does occur—but very rarely, with a spontaneous-fission half-life of about 10¹⁶ years, far longer than its alpha-decay lifetime. In light nuclei the barrier is so high and thick that spontaneous fission is effectively unobservable.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 2 条独立证据
来源 · Source
K. S. Krane,《Introductory Nuclear Physics》(Wiley,1987),第13章(核裂变)
K. S. Krane, 'Introductory Nuclear Physics' (Wiley, 1987), Ch.13 (Nuclear Fission)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780471805533 (1987) · 核验依据 2 ISBN 9780471805533 (1988)
#自发裂变 #液滴模型 #裂变势垒
为什么核电站能产生电？
How can a nuclear plant make electricity?
反应堆其实就是一台烧铀的蒸汽机: 铀-235 裂变放出的动能变成热，慢化剂（轻水、重水或石墨）把中子减速到容易引发下一次裂变的能量，控制棒吸收多余中子把增殖因数 k 稳在 1 附近。带热的水把热量送去蒸汽发生器，推动汽轮机发电，乏汽再在冷凝器里变回水循环使用。能量来源是裂变产物的结合能差，一次裂变约放出 200 MeV；而它的电效率与普通火电相当，约三分之一到四成，剩下的热量必须排给河水、海或冷却塔——这也是核电站临水而建、且常被抱怨热污染的原因。
A reactor is really a steam engine that burns uranium: the kinetic energy of uranium-235 fission becomes heat, a moderator (light water, heavy water or graphite) slows neutrons to the energy where they most easily cause the next fission, and control rods soak up the surplus to hold the multiplication factor k near 1. The hot water carries heat to a steam generator, the steam spins a turbine that makes electricity, and the spent steam is condensed back and reused. The energy source is the binding-energy difference of the fission fragments, roughly 200 MeV per fission; its electrical efficiency is like any thermal plant, about a third to forty percent, and the rest must be dumped to river, sea or cooling towers - which is why reactors sit beside water and draw complaints about waste heat.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04 · 2 条独立证据
来源 · Source
Krane，《原子核物理导论》（第3版）
Krane, 'Introductory Nuclear Physics' (3rd ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780471805533 (1987) · 核验依据 2 ISBN 9780471805533 (1988)
#裂变 #蒸汽 #发电
为什么恒星中质子-质子聚变需要量子隧穿？
Why does proton-proton fusion in stars require quantum tunneling?
两个质子都带正电，要靠近到强相互作用范围需克服约1 MeV的库仑势垒，而核心热运动仅约1 keV；靠麦克斯韦分布的尾部和隧穿，才能以极慢但足够的速率发生聚变。
Two protons must cross a ~1 MeV Coulomb barrier but core thermal energy is only ~1 keV; tunneling through the tail of the Maxwell distribution allows the slow but vital fusion rate.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #聚变 #隧穿
结合能曲线为什么在铁-56附近达到峰值？
Why does the binding-energy curve peak near iron-56?
轻核靠成链增加核子间强相互作用而增益，重核因质子间库仑斥力随 Z² 增长而稀释每个核子的结合能；铁-56每个核子结合最紧，故聚变（轻）与裂变（重）都释放能量。
Light nuclei gain binding per nucleon by adding strong interactions; heavy nuclei lose it to Coulomb repulsion scaling with Z². Fe-56 is most tightly bound, so fusion (light) and fission (heavy) both release energy.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #结合能 #铁56
碳-14测年法为什么能根据骨骸中残存的C-14比例，推算生物死亡至今过了多少年？
Why can carbon-14 dating tell how long ago an organism died from the remaining C-14 in its remains?
活体不断从大气摄取碳-14，死亡后摄入停止，体内 C-14 只按约 5730 年的半衰期衰变减少。测出样品中残存 C-14 与稳定碳的比值，对照初始比值即可反推经过的半衰期数、换算成年代。它适用于数百年到约五万年的有机物。
While alive, organisms keep taking in carbon-14, but after death intake stops and the C-14 decays with a half-life of about 5730 years. Measuring the remaining C-14 versus stable carbon, and comparing to the initial ratio, reveals how many half-lives passed and thus the age. It works for organic material from centuries up to roughly fifty thousand years.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
W. F. Libby,《Radiocarbon Dating》(Univ. of Chicago Press,1952),第1章
W. F. Libby, 'Radiocarbon Dating' (Univ. of Chicago Press, 1952), Ch.1
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL5490109W：Radiocarbon dating（首版 1
#碳-14测年 #半衰期 #放射性衰变
为什么原子核不会因为质子间的电斥力而散开？
Why doesn't the nucleus fly apart from proton repulsion?
强相互作用（核力）在约1飞米距离上远强于电磁力，把质子和中子绑在一起；它短程且对核子数饱和，所以小核稳定、过大的核因表面效应而不稳。
The strong nuclear force at ~1 fm vastly exceeds EM repulsion and binds nucleons; it is short-range and saturating, so small nuclei are stable while very large ones are unstable.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #强相互作用 #结合能
核电站里的链式反应是怎么被控制的？
How is the chain reaction in a nuclear reactor controlled?
铀-235裂变释放的中子被减速剂慢化以提高引发下次裂变的效率；控制棒（如硼、镉）吸收多余中子，调节增殖因数 k 维持在略大于1的稳定功率，而非爆炸式的远超大1。
Moderators slow the neutrons released by uranium-235 fission to raise the chance of the next fission; control rods (boron, cadmium) absorb excess neutrons, keeping the multiplication factor k near 1 for steady power rather than a runaway.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #链式反应 #反应堆
什么是放射性衰变？
What is radioactive decay?
不稳定的原子核会自发放出α、β或γ射线，变成另一种核，这个过程随机发生，但大量原子有固定的半衰期。
An unstable nucleus spontaneously emits alpha, beta, or gamma radiation and becomes a different nucleus. It is random per atom but follows a fixed half-life for a large sample.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Rutherford 与 Soddy，《放射性的起因与本质》，Philosophical Magazine 4 (1902)
Rutherford & Soddy, 'The Cause and Nature of Radioactivity', Philosophical Magazine 4 (1902)
#放射性 #衰变 #半衰期
什么是β衰变中的弱相互作用与中微子？
What are the weak interaction and neutrinos in beta decay?
β衰变中中子变成质子并放出电子和反电子中微子，由弱相互作用介导，涉及 d→u 夸克味变；中微子几乎不相互作用，带走一部分能量动量，最初由泡利为守恒而预言。
In beta decay a neutron becomes a proton plus an electron and antineutrino via the weak force (d→u flavor change); the nearly non-interacting neutrino carries away missing energy, predicted by Pauli for conservation.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #β衰变 #弱力
辐射为什么会伤害身体？
Why is radiation harmful to the body?
高能射线会撞击细胞里的分子、打断 DNA，造成细胞损伤或癌变；剂量越大、时间越长，伤害越严重。
High-energy radiation strikes molecules in cells and breaks DNA, causing damage or cancer; the larger the dose and the longer the exposure, the worse the harm.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
国际放射防护委员会（ICRP），《2007 年建议书》，ICRP 第103号出版物
International Commission on Radiological Protection (ICRP), 'The 2007 Recommendations', ICRP Publication 103
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787502242565（豆瓣书目条目: 国际放射防护委员会2007年建议书）
#辐射 #DNA #伤害
烟雾探测器是怎么用放射性物质报警的？
How does a smoke detector use radioactivity to alarm?
探测器里有微量镅-241发出α粒子，使空气电离形成微弱电流；烟雾进入会阻挡离子、使电流下降，于是触发警报。
A tiny amount of americium-241 emits alpha particles that ionize air into a weak current; smoke entering blocks ions and drops the current, triggering the alarm.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Knoll，《辐射探测与测量》（第4版）
Knoll, 'Radiation Detection and Measurement' (4th ed.)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL471100W：Radiation detection and
#放射性 #烟雾报警 #电离
为什么医生用X光能看见骨头？
Why can X-rays show bones at the doctor?
X光穿透软组织较多、被密度大的骨头吸收较多，底片或探测器上骨头处留下的光少，于是显出亮暗不同的影子，骨头看起来更白。
X-rays pass through soft tissue but are absorbed more by dense bone, so the detector shows bone as a brighter/darker shadow.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #X射线 #吸收
放射性衰变为什么没法精确预测单个原子何时衰变？
Why can't we predict exactly when a single atom decays?
衰变是量子随机过程，每个原子核在单位时间有固定概率 λ 衰变，但单个事件何时发生纯属概率；宏观上大量原子才呈现稳定的半衰期规律。
Decay is quantum-random: each nucleus has a fixed probability λ per unit time, but the exact moment is probabilistic; only large ensembles show a stable half-life.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
程守洙 江之永,《普通物理学》第七版,高等教育出版社,2016
Cheng Shouzhu and Jiang Zhiyong, General Physics, 7th ed., Higher Education Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787040429190（豆瓣书目条目: 普通物理学．上册）
#核 #放射性 #随机