Ultraviolet (Light My Way) Trivia Quiz

Gamma rays have the shortest wavelength of all of the electromagnetic waves, shorter than 100 picometers (but all the way up to the Planck length, in theory). This gives them some overlap with x-rays and the transition from one to the other is not exactly defined, the difference being their origin. The gamma rays come from the nucleus and have the most energy of all of the EM spectrum, while they can penetrate the most as well. The name was coined in 1903 by New Zealand physicist Ernest Rutherford after the alpha and beta rays had already been defined.

Gamma rays typically occur naturally from interactions with cosmic rays as a second radiation emission or as a result of radioactive nuclear decay. They can be generated artificially through fission and fusion, as well as in some high-energy physics experiments.

X-rays have a wavelength of 10 picometers to about 10 nanometers. They were discovered by the German physicist Wilhelm Conrad Röntgen in 1895 and are sometimes named for him. They are highly penetrative and their most known use is in internal imaging, especially in the medical field.

X-rays are commonly generated through interactions of high-energy electrons and an absorbing matter. When the electron gets absorbed, it displaces an electron already existing in the atom and the rest of the electrons have to fill in the resultant gaps. This change in energy releases the electromagnetic radiation in the form of an X-ray photon.

Ultraviolet is a division of the electromagnetic spectrum that ranges in wavelength from 10 nanometers to about 400 nanometers. This light is not visible to humans, but some insects and birds can see part of this spectrum of light. The ultraviolet photons are not energetic enough to cause ionization but they do interact with molecules, and especially with organic ones.

Ultraviolet light is one of the leading reasons for skin cancer and can cause irreparable damage to the DNA molecule in your body. It can be used to sterilize surfaces (as was used to great effect during the coronavirus pandemic) but is also the source of vitamin D in animals. In moderation, it can promote increased skin pigmentation (tanning).

Blue light is usually defined as being between 450 to 495 nanometers in wavelength. It is one of the three primary additive colours in the light colour model, and its division is the second shortest colour identified, after violet.

Having a higher energy than other colours of light, blue can be both harmful and beneficial for humans. In terms of prevalence, blue is the most common colour around us. It is also the main wavelength of light produced by artificial lights, including screens, phones, televisions, and LEDs. Notice how the sky looks blue? That's because blue light tends to scatter less than other colours, and that is the wavelength of light that will reach our eyes.

Blue light will inhibit the body's ability to produce melatonin, a hormone that tells your body that its ready to go to sleep. So, if you're jetlagged and need to stay up later, being outside and receiving blue light will help you adapt to the new time zone you are in because your body will delay producing melatonin at the times that it is used to producing it.

Green light is defined as the light of wavelength from 520 to 560 nanometers. It is a primary additive colour on the light colour model, but not on the subtractive art colour wheel.

Green light is associated with nature, being the colour reflected by chlorophyll, the natural molecule that allows plants to undergo photosynthesis and is the basis for (our) life on the planet. This means that the plants will absorb all colours of visible light other than green, the green being reflected back to our eyes giving the plant its green colour. If you want to observe a plant without disturbing its state, green light is invisible to the plant.

Red is a colour of visible light that is often defined by a wavelength range of 630 to 740 nanometers. In the light colour model, it is considered one of the three additive primary colours. Of the visible light, it has the longest wavelength.

For humans, the red colour is associated with the colour of our blood. It therefore represents things like sacrifice and courage, though, on the other hand, it can also be associated with love and nobility. Red was the colour adopted by communist regimes and is prevalent on many socialist flags. In history, red may have been the easiest colour pigment to create and one of the most prevalent shades in cave drawings.

Infrared radiation is defined as being the part of the electromagnetic spectrum between 780 nanometers and 100 micrometers in wavelength. It is most commonly associated with heat and approximately half of the sun's radiation that reaches the Earth's surface is in these wavelengths.

The concept of infrared radiation was explored even as far back as the 17th century when fires were studied and an explanation was needed on their seemingly-invisible emission of heat. Black-body radiation (radiation that is emitted dependent only on an object's temperature) from objects that are at or near room temperature is mostly in the infrared spectrum. This is why thermal imaging (a form of 'night vision') uses the emitted infrared radiation as a way of constructing a visible-light picture.

Terahertz radiation is a recently-defined part of the electromagnetic spectrum that is between 100 micrometers and 1 millimeter in wavelength. It is a newly-studied division of the electromagnetic spectrum and there are new uses every day for it.

It is called 'terahertz radiation' because the energy carried by the photons in this range have a frequency from 0.3 to 3 terahertz. It can also be called the 'submillimeter band'. It is easily absorbed by the atmosphere and is filtered out from the sun's light from reaching the surface. It can, however, penetrate most fabrics that are worn and give an echo off of metals, making it an effective and safe way of detecting concealed weapons. In dentistry, it is also an effective way of 3D imaging teeth. Attempts at high-altitude communication were effective when using terahertz transmissions.

Despite their misleading name, microwaves are waves often between one millimeter and one meter in wavelength in the electromagnetic spectrum. The division between infrared, microwaves, and radio waves can be pretty arbitrary and there are often different wavelengths given, however, microwaves are always between the radio and infrared ranges (near the terahertz gap).

Microwaves follow a direct line of propagation, do not diffract around terrain or buildings, and do not follow the curvature of the Earth. They also do not reflect off the atmosphere. This makes them good for point-to-point communications, especially since they remain very narrow and do not spread out.

They also agitate polar molecules, like water, which makes them an effective way of heating. Microwave ovens use this to great effect and heat up the water molecules in our food. Since there are no water molecules in the dishes, it is just the food that gets warm. [However, through conduction, the plate may get hot as a secondary effect]

The longest wavelengths in the electromagnetic spectrum belong to radio waves. They are generally defined as being between one meter to kilometers in length. Up to 100 kilometers has been generated to deliver information, however, any longer than that is difficult (and very slow) to be of practical use.

Because radio wavelengths are so long, they can penetrate through foliage, go around terrain, diffract around buildings, and scatter and reflect more often than they're absorbed. This makes them ideal for communication because they can usually be picked up effectively. Underwater, very low frequency waves can reach all the way around the world making it an effective way of reaching a submarine fleet that may not want to disclose its location.