Mercury vapour is used in as the dominant species which is excited in a traditional fluorescent light. The first and second excited states of Mercury occur at 254 and 185 nm.

1. In what region of the electromagnetic spectrum do these transitions occur?
2. Given that these transitions occur mostly outside the visible range, how are these transitions utilised to generate typical room lighting?

Thanks any help will be appreciated.

254 nm is in the UV region of the spectrum; 185 is in the vacuum ultraviolet region.

These wavelengths shine on a fluorescent material that coats the inside of the bulb. The coated is bathed in the UV light, it is absorbed and re-radiated as visible radiation. Here is a site that gives much more information than you are looking for; however, if you will scroll through it, it contains BOTH an explanation of how the fluorescent bulbs work as well as a table of regions where the different
wavelengths fall.
http://en.wikipedia.org/wiki/Ultraviolet

1. To determine the region of the electromagnetic spectrum where these transitions occur, we need to find the corresponding wavelength range. The electromagnetic spectrum ranges from radio waves with long wavelengths to gamma rays with short wavelengths.

We are given that the first excited state of Mercury occurs at 254 nm (nanometers) and the second excited state occurs at 185 nm.

To determine the region of the electromagnetic spectrum, we can refer to the wavelength ranges commonly associated with different parts of the spectrum. In general, the ultraviolet (UV) region of the spectrum ranges from about 10 nm to 400 nm.

So, based on the given wavelengths, the transitions of Mercury occur within the ultraviolet (UV) region of the electromagnetic spectrum.

2. Even though these transitions occur outside the visible range, they are still utilized to generate typical room lighting through a two-step process.

In a fluorescent light bulb, mercury vapor inside the bulb is excited by an electrical discharge, causing the electrons in the mercury atoms to jump from the ground state to higher energy levels. When these excited electrons return to their ground state, they release the excess energy as photons of light.

However, since the transitions in mercury occur primarily in the UV region, the emitted UV light is not directly visible to our eyes. Hence, the process involves phosphor coating on the inside of the fluorescent tube. The phosphor coating absorbs the UV light emitted by the excited mercury atoms and re-emits it at longer wavelengths, shifting the light into the visible spectrum.

This phenomenon, known as fluorescence, converts the UV light into a broader range of wavelengths that fall within the visible range. As a result, we can perceive the light emitted from a fluorescent light bulb as visible light, creating typical room lighting.