# Tag Info

15

If the wave is truly monochromatic then it will be sinusoidal. If it has a different profile then Fourier's theorem tells us that it can be built from an infinite series of (co)sine waves with increasing integer harmonics of the principle frequency (i.e. not monochromatic).

5

A plane wave is a single frequency , a sinusoidal variation in space and time by mathematical construction. Mathematically : the traveling wave solution to the wave equation ... is valid for any values of the wave parameters, and since any superposition of solutions is also a solution, then one can construct a wave packet solution as a sum of ...

5

The electromagnetic field in absence of charges and current is described by a wave equation. The solutions of the wave equations in a general setting (without symmetry contestants and without boundary conditions) are plane waves with a fixed frequency and momentum. These are purely sinusoidal $\propto \sin(k x-\omega t)$. Similarly, sound waves are the ...

3

The trick with invisibility is to arrange the flow of light so that when someone looks towards you they see whatever is behind you. This can be achieved by two methods: either a chameleon-like rapid colouring and patterning of your clothing to make it look like the scenery behind---with a 3d hologram-like effect for the best results. a powerful lens-like ...

3

The intuition that a black hole must have a very large mass is not true. The relevant parameter is how much mass is there within a (volume of some characteristic) radius. In the case of simple spherical objects, if a mass $M$ is concentrated within a radius $2GM/c^2$ then light (or anything else for that matter) cannot escape from the region $r< 2GM/c^2$, ...

2

If monochromatic light shines into our eyes, will that activate multiple types of cones or only one type of cone? Let's take for example monochromatic light with wavelength 520 nm (i.e. a yellow wavelength). Then your diagram (with the spectral sensitivity of the 3 types of cones) answers this question easily. L-type cones respond with strength 0.68 M-...

2

Rule One: Have Fun. Now, on to the optics. The refractive index is a bulk property of the material which means you cannot affect it with tiny amounts of things like food colorants. You can affect it with bulk constituents, like by adding sugar to water; in fact there is a handy little gizmo called a refractometer which is used by winemakers to tell how ...

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I'd like to challenge your idea that the fact that a mix of red and blue gives something resembling violet implies that violet must be between red and blue. In practice, what you get from such mixture is a shade of purple. See the figure below. Here the black dashed line from blue to red covers the colors you can get by changing the amount of red and blue ...

1

Color is a double valued concept, different in physics and in perception. In Physics there is a one to one correspondence between color seen in the visible spectrum and the frequency of light. Electromagnetic spectrum with visible light highlighted The whole electromagnetic spectrum covers many frequencies above an below the visible, which are the ...

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