📚 Ultraviolet Radiation: The 370 nm Wavelength | 紫外线：370纳米波长
Ultraviolet (UV) radiation is a form of electromagnetic wave that sits just beyond the violet end of the visible spectrum. Wavelengths around 370 nanometres (nm) fall within the UVA band, making them an excellent case study for IGCSE Science students exploring wave properties, energy transfer, and biological interactions. This article unpacks the physics of 370 nm UV, its real‑world applications, and the safety measures you need to know for Edexcel IGCSE.
紫外线（UV）是一种电磁波，位于可见光谱紫色端之外。波长约 370 纳米（nm）的光属于 UVA 波段，这使它成为 IGCSE 科学学生学习波动性质、能量传递和生物相互作用的绝佳案例。本文将剖析 370 纳米紫外线的物理原理、实际应用，以及 Edexcel IGCSE 考试中你需要掌握的安全措施。
1. The Electromagnetic Spectrum and Where UV Fits | 电磁波谱与紫外线的位置
gth, from long radio waves to extremely short gamma rays. Ultraviolet radiation occupies the region between visible light (starting at about 400 nm) and X‑rays (down to around 10 nm). The wavelength of 370 nm places it in the near‑UV, specifically the UVA sub‑band, which is the least energetic but most abundant form of UV reaching Earth’s surface.
电磁波谱是一个连续的波段，所有电磁波在真空中均以光速（3.00 × 10⁸ m/s）传播。它按波长排列，从长波无线电波到极短的伽马射线。紫外线位于可见光（约 400 nm 起始）与 X 射线（低至约 10 nm）之间。370 nm 的波长属于近紫外线，具体为 UVA 子波段，这是能量最低但到达地球表面最丰富的紫外线形式。
All electromagnetic waves share key properties: they are transverse, can travel through a vacuum, and their energy is directly proportional to frequency and inversely proportional to wavelength. The wave equation links speed (c), frequency (f), and wavelength (λ):
所有电磁波具有共同特性：它们是横波，能在真空中传播，其能量与频率成正比、与波长成反比。波动方程将速度（c）、频率（f）和波长（λ）联系起来：
c = f × λ
or 370 nm UV (λ = 3.70 × 10⁻⁷ m), the frequency calculates to approximately 8.11 × 10¹⁴ Hz – photon energy to cause chemical changes, a concept crucial for understanding its effects.
对于 370 纳米紫外线（λ = 3.70 × 10⁻⁷ m），频率计算约为 8.11 × 10¹⁴ Hz，远高于可见光的频率。较高的频率赋予紫外线足够的光子能量来引发化学变化，这是理解其影响的关键概念。
2. Characteristics of Ultraviolet Radiation | 紫外线的特性
UV radiation is invisible to the human eye, yet it can be detected by fluorescent materials, photographic film, and electronic sensors. It is subdivided into three main bands based on wavelength and biological impact: UVA (400–315 nm), UVB (315–280 nm), and UVC (280–100 nm). 370 nm sits comfortably in the UVA range, which is less harmful than UVB or UVC, but still capable of penetrating deep into the skin’s dermis layer.
紫外线对人眼不可见，但可通过荧光材料、照相胶片和电子传感器检测到。根据波长和生物影响，紫外线分为三个主要波段：UVA（400–315 nm）、UVB（315–280 nm）和 UVC（280–100 nm）。370 nm 稳稳位于 UVA 范围内，它比 UVB 或 UVC 危害小，但仍能穿透皮肤的真皮层。
Key properties of UV at 370 nm include its ability to cause fluorescence – many substances absorb 370 nm radiation and re‑emit longer visible light, a phenomenon used in forensic science and anti‑counterfeiting. UV also promotes the production of vitamin D in the skin, though excessive exposure can degrade collagen and lead to premature ageing. Because UVA is less energetic than UVB, it does not directly damage DNA as readily, but it can generate reactive oxygen species that cause indirect cellular damage.
370 纳米紫外线的关键特性包括其引发荧光的能力——许多物质吸收 370 纳米辐射并重新发出更长的可见光，这一现象被用于法医学和防伪。紫外线还能促进皮肤中维生素 D 的生成，但过度暴露会降解胶原蛋白并导致过早衰老。由于 UVA 能量低于 UVB，它不易直接损伤 DNA，但会产生造成间接细胞损伤的活性氧物种。
3. 370 nm UVA: Properties and Position in the Spectrum | 370 纳米 UVA：性质与谱中位置
A wavelength of 370 nm falls near the middle of the UVA window, sometimes designated as UVA‑I (340–400 nm). This radiation has a photon energy of about 3.35 electronvolts (eV), which is sufficient to excite electrons in atoms and molecules but not typically strong enough to ionise them. That is why UVA is classified as non‑ionising radiation, yet its ability to stimulate photochemical reactions cannot be ignored.
370 纳米波长接近 UVA 窗口的中段，有时被划分为 UVA‑I（340–400 nm）。该辐射的光子能量约为 3.35 电子伏特（eV），足以激发原子和分子中的电子，但通常不足以使其电离。这就是 UVA 被归为非电离辐射的原因，但其激发光化学反应的能力不可忽视。
When 370 nm UV strikes a material, it can be reflected, transmitted, or absorbed. The absorbed energy may be converted into heat or re‑emitted as lower‑energy photons. For example, many white fabrics and optical brighteners glow under 370 nm black lights because they absorb the UV and fluoresce in the blue region of the visible spectrum. This interaction makes UVA LEDs at 370 nm popular for currency verification and scientific imaging.
当 370 纳米紫外线照射材料时，可被反射、透射或吸收。吸收的能量可能转化为热，或作为低能光子重新发射。例如，许多白色织物和光学增白剂在 370 纳米黑光下会发光，因为它们吸收紫外线并在可见光谱的蓝区发出荧光。这种相互作用使 370 纳米的 UVA LED 广泛用于货币验证和科学成像。
4. Detection and Measurement of UV at 370 nm | 370 纳米紫外线的检测与测量
Detecting UVA radiation at 370 nm often relies on semiconductor photodiodes or photomultiplier tubes that are sensitive to those wavelengths. In the school laboratory, UV‑sensitive beads or UV‑detector cards provide a simple, qualitative demonstration. These beads contain photochromic pigments that change colour rapidly when exposed to UV around 370 nm, a practical way for IGCSE students to visualise the presence of invisible radiation.
检测 370 纳米 UVA 辐射通常依赖对该波长灵敏的半导体光电二极管或光电倍增管。在学校实验室中，紫外线感应珠或紫外线检测卡可提供简单的定性演示。这些珠子含有光致变色颜料，暴露在约 370 纳米紫外线下会迅速变色，是 IGCSE 学生可视化不可见辐射存在的实用方法。
Quantitative measurement uses UV radiometers calibrated to specific UVA spectra. For the wave equation and energy calculations, students need to recall that photon energy E is given by:
定量测量使用校准至特定 UVA 光谱的紫外线辐射计。在波动方程和能量计算中，学生需记住光子能量 E 由下式给出：
E = h × f
¹⁹ J, or about 3.35 eV. This calculation appears frequently in Edexcel IGCSE Physics multi‑ equency, and photon energy to explain why UV but not visible light can disinfect surfaces.
式中 h 为普朗克常数（6.63 × 10⁻³⁴ J·s）。代入 370 纳米的频率，可得 E ≈ 5.37 × 10⁻¹⁹ J，约为 3.35 eV。此类计算经常出现在 Edexcel IGCSE 物理的多步问题中，通常将波长、频率和光子能量联系起来，以解释为何紫外线而非可见光可为表面消毒。
5. Biological Effects of 370 nm UV | 370 纳米紫外线的生物影响
While UVA at 370 nm is less directly genotoxic than UVB, it penetrates deeper into the skin and can generate free radicals that damage collagen, elastin, and DNA over time. This accelerates photoageing and contributes to the development of skin cancers. IGCSE Biology students should note that UVA is present all year round and can even pass through glass, unlike UVB which is mostly filtered by glass.
尽管 370 纳米 UVA 的直接遗传毒性弱于 UVB，但它能更深地穿透皮肤，并产生自由基，随着时间推移损伤胶原蛋白、弹性蛋白和 DNA。这会加速光老化并促成皮肤癌的发生。IGCSE 生物学生应注意，UVA 全年存在，甚至能穿透玻璃，而 UVB 则大部分被玻璃过滤。
The eye is also vulnerable: UV at 370 nm can be absorbed by the cornea and lens, potentially leading to cataracts. On the positive side, controlled exposure to UVA is used in phototherapy to treat skin conditions such as eczema and psoriasis, often combined with psoralen drugs in PUVA therapy. Understanding these dual effects is a classic exam theme on risks and benefits of electromagnetic radiation.
眼睛同样易受伤害：370 纳米紫外线可被角膜和晶状体吸收，可能导致白内障。从积极的一面看，在光疗中利用受控的 UVA 暴露治疗湿疹和牛皮癣等皮肤病，常与补骨脂素药物结合用于 PUVA 疗法。理解这些双重效应是有关电磁辐射风险与益处的经典考试主题。
6. UV in Medicine and Sterilisation | 紫外线在医学与消毒中的应用
Although UVC is the most powerful sterilising UV band, 370 nm UVA still contributes to antimicrobial action when used in combination with photosensitisers. In disinfection cabinets and water purification units, broad‑spectrum UV lamps emitting a peak at around 370 nm can inactivate bacteria and viruses by inducing oxidative stress. This application relies on the fact that microorganisms do not have protective skin layers and are more susceptible to photochemical damage.
虽然 UVC 是消毒能力最强的紫外线波段，但 370 纳米 UVA 与光敏剂结合使用时仍能发挥抗菌作用。在消毒柜和水净化装置中，峰值约在 370 纳米的广谱紫外线灯可通过诱导氧化应激灭活细菌和病毒。该应用依赖于微生物没有保护性皮肤层，因而更易受光化学损伤这一事实。
In medical diagnostics, 370 nm light sources excite fluorescent markers attached to antibodies, enabling the imaging of specific cells or proteins. This technique, known as immunofluorescence, is a cornerstone of modern pathology. The wavelength is chosen to match the excitation peak of fluorescent dyes such as DAPI or FITC, which emit visible light for detection. Students can relate this to energy level diagrams: absorption of a 370 nm photon raises an electron to an excited state, and the subsequent emission produces a photon of lower energy and longer wavelength.
在医学诊断中，370 纳米光源可激发附着在抗体上的荧光标记物，从而对特定细胞或蛋白质进行成像。这项技术称为免疫荧光，是现代病理学的基石。所选波长与 DAPI 或 FITC 等荧光染料的激发峰匹配，这些染料发出可检测的可见光。学生可将其与能级图联系起来：吸收一个 370 纳米光子使电子跃迁至激发态，随后发射出能量更低、波长更长的光子。
7. Industrial and Scientific Uses of 370 nm UV | 370 纳米紫外线的工业和科学用途
370 nm UVA LEDs are widely used in curing adhesives, printing inks, and coatings. Photoinitiators in these materials absorb the UV and trigger rapid polymerisation, turning a liquid into a solid in seconds. This application appears in IGCSE Chemistry when discussing polymers and cross‑linking, and it demonstrates how electromagnetic waves can drive chemical change.
370 纳米 UVA LED 广泛用于固化粘合剂、印刷油墨和涂料。这些材料中的光引发剂吸收紫外线并触发快速聚合，在数秒内将液体变为固体。该应用出现在 IGCSE 化学讨论聚合物和交联时，同时展示了电磁波如何驱动化学变化。
Forensic scientists use 370 nm light sources to reveal bodily fluids, fingerprints, and counterfeit documents. Many biological stains fluoresce under UVA without the need for chemical developers, preserving the evidence. In the textile and paper industries, optical brightening agents are designed to absorb ambient UV and re‑emit blue light, making products appear whiter and brighter – an everyday example of 370 nm interactions that students can easily spot.
法医科学家使用 370 纳米光源揭示体液、指纹和伪造文件。许多生物污渍在 UVA 下发出荧光，无需化学显影剂，从而保留了证据。在纺织和造纸工业中，光学增白剂被设计为吸收环境紫外线并重新发出蓝光，使产品看起来更白更亮——这是学生能轻易察觉的 370 纳米相互作用的日常实例。
8. UV and the Ozone Layer | 紫外线与臭氧层
The Earth’s stratospheric ozone layer is a critical shield that absorbs most of the harmful UVB and UVC radiation from the Sun. However, UVA, including 370 nm, is not significantly absorbed by ozone. Approximately 95% of the UV reaching the ground is UVA. This is why even on cloudy days, UVA levels can remain high enough to cause skin damage, an important point for IGCSE students studying the atmosphere and environmental protection.
地球平流层臭氧层是关键的屏障，吸收大部分来自太阳的有害 UVB 和 UVC 辐射。然而包括 370 纳米在内的 UVA 并未被臭氧显著吸收。到达地面的紫外线中约 95% 是 UVA。这就是即使阴天，UVA 水平仍可高到足以造成皮肤损伤的原因，这对学习大气和环境保护的 IGCSE 学生而言是重要的一点。
Ozone depletion by chlorofluorocarbons (CFCs) has historically increased UVB levels, but the UVA flux has remained relatively stable. Nevertheless, because UVA contributes to long‑term skin damage and immune suppression, public health guidance now emphasises broad‑spectrum sunscreens that block both UVA and UVB. Products labelled with a UVA star rating or the "UVA" logo inside a circle are tested to ensure adequate protection at wavelengths like 370 nm.
历史上的氯氟烃（CFCs）消耗臭氧层虽增加了 UVB 水平，但 UVA 通量保持相对稳定。然而，由于 UVA 会导致长期皮肤损伤和免疫抑制，公共卫生指南现强调使用能同时阻挡 UVA 和 UVB 的广谱防晒霜。标注有 UVA 星级或在圆圈内有“UVA”标志的产品经测试可确保在 370 纳米等波长下提供足够防护。
9. Safety Precautions: Working with 370 nm UV Sources | 安全防护：使用 370 纳米紫外线源
When handling 370 nm UV lamps in the laboratory, safety goggles with UV‑blocking filters are essential. Even though UVA is less intense than UVC, prolonged exposure can cause 'welder’s flash' or photokeratitis, a painful inflammation of the cornea. IGCSE practicals involving UV should always include a clear risk assessment mentioning eye protection, skin cover, and limiting exposure time.
在实验室操作 370 纳米紫外线灯时，必须佩戴具有防紫外线滤光片的护目镜。尽管 UVA 强度低于 UVC，长时间暴露仍可导致“焊工闪”或光性角膜炎，即角膜疼痛性炎症。涉及紫外线的 IGCSE 实验应始终包括明确的风险评估，提及眼部防护、皮肤遮盖和限制暴露时间。
The inverse square law applies to UV intensity: doubling the distance from the source reduces the intensity to one quarter. This principle can be used to set safe working distances. In industry, interlocks and shielding prevent accidental exposure. For personal safety, wearing tightly woven clothing and broad‑brimmed hats offers physical UVA protection. Sunscreens containing titanium dioxide or zinc oxide work by reflecting and scattering 370 nm radiation, while chemical absorbers convert UV energy into heat.
平方反比定律适用于紫外线强度：与光源的距离增大一倍，强度降至四分之一。该原理可用于设定安全工作距离。在工业中，联锁装置和屏蔽罩防止意外暴露。在个人防护方面，穿着紧密编织的衣物和宽边帽可提供物理性 UVA 防护。含有二氧化钛或氧化锌的防晒霜通过反射和散射 370 纳米辐射发挥作用，而化学吸收剂则将紫外线能量转化为热量。
10. Summary and Exam Focus for Edexcel IGCSE Science | 总结与 Edexcel IGCSE 科学考试重点
370 nm UV radiation serves as a perfect anchor point for revising several IGCSE Science topics: electromagnetic spectrum ordering, the wave equation, photon energy calculations, ionising versus non‑ionising radiation, biological effects, and environmental relevance. Typical Edexcel questions may ask you to calculate frequency from wavelength, compare the penetrating power of UVA and UVB, or suggest why UV curing is more energy‑efficient than thermal drying.
370 纳米紫外线是复习多个 IGCSE 科学主题的绝佳切入点：电磁波谱排序、波动方程、光子能量计算、电离与非电离辐射、生物效应和环境关联。常见的 Edexcel 考题可能要求你根据波长计算频率、比较 UVA 与 UVB 的穿透能力，或解释为何紫外线固化比热干燥更节能。
Remember these quick facts for your examination: UVA (320–400 nm) is the longest‑ is about 3.35 eV; it causes fluorescence and photoageing; most of it passes through the ozone layer; and protection requires broad‑spectrum measures. Linking wave properties to real‑world contexts will strengthen your application marks.
在考试中请记住这些快速要点：UVA（320–400 nm）是波长最长的紫外线波段；370 纳米 UVA 频率约为 8.1 × 10¹⁴ Hz；其光子能量约为 3.35 eV；它能引起荧光和光老化；大部分能穿透臭氧层；防护需采用广谱措施。将波动性质与现实场景联系起来，将提升你的应用分析得分。
Published by TutorHao | Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图