Boundary Behavior of Waves and Polarization · 波的边界行为与偏振
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| polariser/ˈpəʊlɑːraɪzə/ | 偏振片 | piān zhèn piàn |
Why polarised sunglasses kill the glare off water
- Slip on polarised sunglasses and the harsh glare off a lake or road just melts away.
- They work by blocking light that vibrates in one particular direction.
- That trick only works on transverse waves — and it reveals what happens when waves meet a boundary.
- Boundaries reflect, transmit and filter waves in useful ways.
为什么偏振太阳镜能消除水面的眩光
- 戴上偏振太阳镜,湖面或路面刺眼的眩光就消失了。
- 它们通过阻挡沿某个特定方向振动的光来工作。
- 这个把戏只对横波有效——它揭示了波遇到边界时会发生什么。
- 边界以有用的方式反射、透射和过滤波。
What happens at a boundary
- When a wave hits a boundary between two media, part is reflected and part is transmitted.
- The transmitted part refracts (bends) as its speed changes, as we saw with light.
- A wave reflecting off a denser medium can flip (invert) — important for standing waves.
- How much reflects vs transmits depends on how different the two media are.
边界处发生什么
- 当波打到两种介质之间的边界时,一部分被反射,一部分被透射。
- 透射的部分随速率改变而折射(弯折),正如我们看到的光。
- 从较密介质反射的波可以翻转(倒相)——对驻波很重要。
- 反射与透射的多少,取决于两种介质相差多大。
When a wave meets a boundary between two media, it generally: · 当波遇到两种介质的界面时，通常：
Part of the wave reflects and part transmits (refracting) at a boundary. · 部分波反射，部分透射（折射）通过界面。
Polarisation
- A transverse wave vibrates in a plane; ordinary light vibrates in all directions at once (unpolarised).
- A polariser 偏振片 lets through only the vibrations in one direction — polarised light.
- Cross two polarisers at right angles and no light gets through.
- Reflected glare is partly polarised, which is why polarised lenses can block it.
偏振
- 横波在一个平面内振动;普通光同时在所有方向上振动(非偏振)。
- 偏振片只让沿一个方向的振动通过——偏振光。
- 把两片偏振片成直角交叉,就没有光能通过。
- 反射的眩光部分偏振,这就是偏振镜片能挡住它的原因。
A transverse wave to polarise · 使横波发生偏振
See a transverse wave vibrating in a plane — the kind a polariser can filter. · 观察在一个平面内振动的横波——这是偏振器可以过滤的类型。
Two polarisers are crossed at right angles. How much light passes through both? · 两个偏振器相互垂直放置。透过两者的光量是多少？
The second polariser blocks the direction the first passed, so almost no light gets through. · 第二个偏振器阻挡了第一个透过的方向，因此几乎无光通过。
Select all · 所有 true statements about polarisation and boundaries. · 选择关于偏振和边界的所有正确陈述。
Polarisers filter one direction (transverse only), and boundaries split waves. Sound (longitudinal) cannot be polarised. · 偏振器过滤单一方向（仅限横波），界面分割波。声波（纵波）不能被偏振。
Only transverse waves polarise
- Because sound is longitudinal (it vibrates along its travel), it cannot be polarised.
- The fact that light can be polarised is direct proof that light is a transverse wave.
- Polarisation is used in sunglasses, LCD screens and stress-testing materials.
- It is one of the clearest ways to tell a transverse wave from a longitudinal one.
只有横波才能偏振
- 因为声是纵波(它沿传播方向振动),它无法被偏振。
- 光能被偏振这一事实,直接证明了光是横波。
- 偏振被用于太阳镜、LCD 屏幕和材料应力测试。
- 它是区分横波与纵波最清楚的方法之一。
Which type of wave can be polarised? · 哪种类型的波可以被偏振？
Only transverse waves vibrate in a plane, so only they can be polarised. · 只有横波在特定平面内振动，因此只有横波能被偏振。
Sound cannot be polarised because it is a longitudinal wave. · 声波不能被偏振，因为它是纵波。
Sound vibrates along its travel direction, so there is no cross-direction to filter. · 声波沿传播方向振动，没有横向维度可供过滤。
The fact that light can be polarised proves light is a ____ wave. · 光可以被偏振这一事实证明光是 ____ 波。
Only transverse waves can be polarised, so light must be transverse. · 只有横波能被偏振，因此光必须是横波。
Only transverse waves can be polarised — sound cannot, because its vibration is along the direction of travel, not across it. If a wave can be polarised, that alone proves it is transverse.
只有横波才能被偏振——声不能,因为它的振动沿传播方向,而非横越它。如果一道波能被偏振,单凭这一点就证明它是横波。
Unpolarised light passes through one vertical polariser, then a second polariser turned to horizontal. How much light emerges?
- The first makes the light vertically polarised.
- The second (horizontal) blocks vertical vibrations, so almost no light gets through.
非偏振光先通过一片竖直偏振片,再通过一片转到水平的偏振片。有多少光出射?
- 第一片使光竖直偏振。
- 第二片(水平)挡住竖直振动,所以几乎没有光能通过。
At a boundary, a wave partly reflects and partly transmits (refracting). A polariser passes only one vibration direction, giving polarised light — possible only for transverse waves. That light polarises (and sound does not) proves light is transverse.
在边界处,波部分反射、部分透射(折射)。偏振片只透过一个振动方向,给出偏振光——只对横波可能。光能偏振(而声不能)证明光是横波。