1) Californium-253 has a half-life of 18 days. Calculate how long it would take for the radioactive count in a sample to decrease from 4Bq to 0.25Bq (2 marks) 2) Carbon – 14 has a half-life of 5700 years. A count begins at 200 and many years later the count is done again and it is now 150. How many years later was that second count done? (2 marks)

3) The radioactive count of Rn-222 takes a 30.4 days to fall from 80000Bq to 312.5Bq. What is the half-life of Rn-222? (2 marks)

4) A man has just found what he believes to be a really old coin with his metal detector. Upon testing in the laboratory, the coin is found to have a C-14 reading of 1.6Bq. If the coin is believed to be 11400 years old and the half-life of C-14 is 5700 years, estimate the reading on the coin when it was new (3 marks)

5) The isotope Pu-238 has a half-life of 87.7 years and can be used to power generators. A generator contains 925g of Pu-238 and 1g of Pu-238 has a powe

Kuoliui10 poils)after creating a brief outline with bulleted points for an essay, which of the followingsteps will you need to complete next? support your ideasproofread for grammar mistakesreconsider your topicnone of the above

Read the passage. the dust bowl during the 1930s, extreme drought and high winds made life incredibly difficult in the great plains region of the united states. in many areas, rainfall was forty percent less than normal. the soil became extremely dry, and when strong winds blew, they created tremendous dust storms. these so-called “black blizzards” were so thick that they made daylight seem like dusk. during this terrible period, the great plains region of the united states was named the “dust bowl.” over the next few years, the drought continued, and the winds created more dust storms. in some places, the drought and high winds lasted for eight years. many people wondered if the black blizzards would ever end. which statement about this paragraph’s main idea is true? this paragraph’s main idea is stated in the topic sentence. there are not enough details to support the main idea. this paragraph’s main idea is implied. this paragraph does not express a main idea.

Taking initiative turns an idea into reality. what is an idea that you've had, a dream or a big goal? how could you take initiative, even a small step, to turn that idea into something tangible?