Fragments of an explosive device, a radiation warning sign in the foreground, are displayed by Ukrainian authorities after a drone attack at the former Chernobyl nuclear power plant, Ukraine, Friday, February 14, 2025.
| Photo Credit: AP
Questions:
1. There are four ways to measure radiation dose. Of these, gray and X measure the absorbed dose whereas sievert and Y measure it in terms of its biological effect. Name X and Y, which are the corresponding non-SI units in these categories.
2. About 0.4 micro-sievert is the amount of radiation your body is exposed to every hour. What is the collective name for the source of this radiation?
3. Name the city in southeast China that is reputed for an area with a particularly high level of radiation — about 6.4 milli-sievert per year — as a result of rocks in the area being particularly rich in uranium and thorium.
4. For humans to be killed by radiation poisoning, the value of the ____ is 4,800 milli-sievert. Fill in the blank with a unit that denotes the amount of a substance required to kill half the members of a population.
5. Name the bacteria famed for being the most radiation-tolerant organism known in existence. It can withstand up to 30,000 gray of gamma rays — 6,000-times higher than the dose that could kill a human.
Visual:
Name this Canadian chemist of the Manhattan Project who died in May 1946 after accidentally, and infamously, setting off a fission reaction in close quarters and receiving a radiation dose of 21,000 sievert.
Answers:
1. Rad and rem
2. Natural background radiation
3. Yangjiang
4. LD50
5. Thermococcus gammatolerans
Visual: Louis Slotin
Published – February 26, 2025 11:00 am IST
