## How long will it take the 40 grams of I 131?

How long will it take for a 40.0 gram sample of I-131 (half life = 8.040 days) to decay to 1/100 its original mass? 1/100= 0.01. Suppose that n – is number of half lifes, then (1/2)n = 0.01 then n = 6.64. So, the time is 6.64*8.040 = 53.4days.

## What fraction of uranium 238 that was present when Earth was formed still remains?

The half life of Uranium-238 is 4.5 billion years and the age of earth is 4.5 billion years . What fraction of Uranium-238 that was present when Earth was formed still remains? _Only a single half live (4.5 Billion years) so ½ remains.

## What is the half-life of uranium-238 quizlet?

4.5 billion years

## Why is lead found in all deposits of uranium ores?

All uranium isotopes are radioactive. Uranium isotopes will decay overtime and become the isotopes of lead. These are the end products of the decay chain of uranium. That is why lead is found in all deposits of uranium ore.

## What happens to the uranium 235 nucleus when it is stretched out?

If the uranium nucleus is stretched into an elongated shape, electrical forces may push it into an even more elongated shape. In a typical example of nuclear fission, one neutron starts the fission of the uranium 235 atom and three more neutrons are produced when the uranium fissions.

## Why is there more carbon 14 in living bones than in once living ancient bones of the same mass?

Why is there more carbon-14 in living bones than in once-living ancient bones of the same mass? The carbon-14 is radioactive and is decaying, therefore depleting all the time. Hence, there is more Carbon-14 in bones of living objects as compared to the dead.

## Is nuclear force attractive or repulsive?

The nuclear force is powerfully attractive between nucleons at distances of about 1 femtometre (fm, or 1.0 × 10−15 metres), but it rapidly decreases to insignificance at distances beyond about 2.5 fm. At distances less than 0.7 fm, the nuclear force becomes repulsive.

## How is carbon-14 produced in the atmosphere?

Carbon-14 is produced in the stratosphere by nuclear reactions of atmospheric nitrogen with thermal neutrons produced naturally by cosmic rays (with the highest production rate 10 to 13 miles above Earth’s poles), as well as by atmospheric nuclear weapons testing in the 1950s and ’60s.

## What is the origin of most of the radiation you encounter?

An electron ejected from an atomic nucleus during the radioactive decay of certain nuclei. High-energy radiation emitted by the nuclei of radioactive atoms. What is the origin of most of the radiation you encounter? The leading source of natural occurring radiation is radon-222, cosmic, ground and human tissue.

## Why is radiation harmful to both living and nonliving things?

Long-term or high-dose exposure to radiation can harm both living and nonliving things. Radiation knocks electrons out of atoms and changes them to ions. It also breaks bonds in DNA and other compounds in living things. Exposure to higher levels of radiation can be very dangerous, even if the exposure is short-term.

## How can electromagnetic radiation affect living things?

Some forms of electromagnetic radiation, which is radiation found in different kinds of light waves, including ultraviolet light and X-rays, can cause damage to the DNA inside a living cell. When DNA is damaged by radiation, it can lead to cell death or to cancer.

## How does radiation affect the environment?

Similarly to humans and animals, plants and soil are also affected negatively from high amounts of nuclear radiation. Just like in humans, radioactive material can damage plant tissue as well as inhibit plant growth. Mutations are also possible due to the damage caused to the DNA.

## How long does radiation last in the environment?

Some stay in the environment for a long time because they have long half-lives, like cesium-137, which has a half-life of 30.17 years. Some have very short half-lives and decay away in a few minutes or a few days, like iodine-131, which has a half-life of 8 days.