Question

There is a form of light that is very energetic and can cause damage to living cells and tissues. The sun emits this type of light, but much of it is blocked by ozone in the atmosphere. Because this type of light can be so damaging to cells, it is often used to kill bacteria in drinking water. The light is shined on contaminated water, and this makes the water clean and healthy for drinking. What type of light is this?

1) Visible light
2) Infrared light
3) Radio waves
4) Ultraviolet light

Answer 1

The type of light that can cause damage to living cells and tissues, is blocked by the ozone layer, and can be used to purify drinking water by killing bacteria is ultraviolet (UV) light. It operates within certain wavelengths that can mutate DNA and kill microorganisms, while also having beneficial applications like stimulating vitamin D production in the human skin.

Step-by-step explanation:

The type of light described in the question that is very energetic and can cause damage to living cells and tissues is ultraviolet (UV) light. This light is emitted by the sun and has shorter wavelengths than visible light, making it more energetic. UV light is capable of causing thymine dimers in DNA, leading to mutations and the death of microorganisms. This makes UV light an effective tool for purifying drinking water and controlling microbial growth. It's employed in water purification systems, both in homes and portable versions for outdoor use. UV light can harm larger organisms like humans, leading to skin cancer and cataracts due to its ability to damage DNA and cells.

The protective ozone layer in Earth's atmosphere absorbs most of the harmful UV light, particularly the more dangerous UV-C and UV-B wavelengths. However, UV-A, which is the least harmful of the three types, still reaches the Earth's surface. Despite its dangers, UV light has beneficial uses, such as the production of vitamin D in the skin and the treatment of infantile jaundice through phototherapy.