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

second person

explanation:

note the heavy uses of "you", "your", as well as "he".

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the miracle worker themeswilliam gibson

themes and meanings

(comprehensive guide to drama)

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there are two central themes in  the miracle worker: that the human spirit can triumph over even the most daunting of disabilities and that a dedicated teacher can transform the lives of those with whom he or she comes into contact. these inspirational themes have long been personified in the widely known true-life relationship between helen keller and annie sullivan, but  the miracle worker  also dramatizes collateral issues that extend beyond the particular case. underlying helen’s process of learning basic principles of what annie terms “obedience” (decorum, etiquette, and hygiene), there are more universal lessons of self-governance—the inculcation of self-restraint instead of willfulness, the development of self-discipline instead of self-indulgence. only when these lessons have been mastered can helen begin to acquire language—which, annie says, “is to the mind more than light is to the eye.”

formal arguments

in written, formal arguments, the best way to build credibility with readers is to provide them with evidence. no matter what your argument might be and which side you agree with, citing strong evidence to back up your claim leaves the opposition with little to argue.

emotional appeal is often used in oral arguments. written arguments, however, rely on four main types of evidence. as you read further, you will see that some types are more credible than others and "hold more water" so to speak.

statistical evidence

the strongest type of evidence in formal writing is statistical evidence. this ranges from true, hard data presented as a percentage or number, to survey-type data. for example, statistical evidence could be:

4 out of 5 experts claim

85% of women in the united

7 members were present

statistical evidence can be proven as fact. you can actually go out and find hard information to prove your particular claim.

testimonial evidence

the use of celebrities as credibility evidence can be considered testimonial in nature. many people look up to celebrities as role models in their lives. good or bad, when a person chooses a life-path that takes them into public light, there will be many others out there who want to emulate the celebrity. these celebrity endorsements provide the second-strongest type of evidence found in formal arguments.

testimonial evidence can also be collected from experts and authorities in a given field. doctors, dentists, lawyers often provide expert testimonials. their authority is not often questions. they are expected to "know their stuff."

anecdotal evidence

when storytelling is involved as evidence, anecdotal evidence is being used. due to its less objective nature, anecdotal evidence is not extremely strong. when coupled with statistical or testimonial evidence, anecdotal evidence can be highly effective in determining credibility or proof.

storytelling, although based on fact, can include quite a bit of opinion, thus making it less objective. usually, eyewitnesses are used as providers of anecdotal evidence. they saw or experienced the phenomenon at hand are telling their version or side of the story.

analogical evidence

when information is scarce about something and little is known, analogical evidence is often used in a formal argument to increase credibility of the proof. if the phenomenon in question is new and little is known about it, analogical evidence that pulls in known factors about a similar phenomenon to show parallels can be an effective way to provide proof.

due to limited knowledge about the phenomenon, in this situation, analogical evidence can be regarded as the weakest type of evidence used in formal arguments. one can only imagine and hope that the comparison-phenomenon is close enough that the results can be applied to the new phenomenon.

in the

all that really matters in a formal argument is whether or not the writer has credible evidence to back up what they want to say or what they are thinking. so often, we hear people say, "prove it! " to one another.

one last little formal arguments not only provide credible evidence to support claims, don't forget that acknowledgment of the opposing point of view in an argument also strengthens the entire product.

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