Awooden object from a prehistoric site has a carbon-14 activity of 10 counts per minute (cpm) compared to 40 cpm for new wood. if carbon-14 has a half-life of 5730 years, what is the age of the wood? explain your steps and conversions.

Explanation:

While trees are alive, they exchange carbon with the atmosphere and the content of carbon-14 remains constant. Once, the plants die the exchange of carbon with the atmospher ends, and carbon-14 content will decrease only by the radioactivity.

Thus, it is assumed that when the prehistorical object was manufactured the carbon-14 activity was 40 cpm (that of new wood), and the ratio of the current carbon-14 activity 10 cpm is related with the number of half-lives elapsed since the object was manufactured in this way:

Where n is the number of half-lives elapsed.

Hence, you can do the calculations:

As stated that carbon-14 has a half-life of 5730 year, and we obtained that two half-lives have elapses, 2 × 5730 years = 11,560 years is the age ot the wood.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.

a is the correct answer