Please help with these questions Part B Half-Life and Radioactive Dating How man

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Please help with these questions

Part B Half-Life and Radioactive Dating How many nuclei are left after a time 2Thalf? Express your answer in terms of and/or No Learning Goal To understand decay in terms of half-life and to solve radioa ctive dating problems. Suppose a radioactive sample initially contains No unstable nuclei. These nuclei will decay into stable nuclei, and as they do, the number of unstable nuclei that remain, N(t), will decrease with time. Although there is no way for us to predict exactly when any one nucleus will decay, we can write down an expression for the total number of unstable nuclei that remain after a time t Submit My Answers Give Up The decay of radioactive nuclei can be used to measure the age of artifacts, fossils, and rocks. Dating an organic artifact entails looking at its carbon content. Carbon exists in three isotopic forms: 12C, 13C, and 1C. Both 12C and 13C are stable, whereas C is radioactive. To find the age of an organic artifact, you measure how much C is found within it today [i.e., N(t)], and you estimate how much would have been in it when it was first made (No). Knowing that the half-life of C is 5730 years, you can use the decay equation to find out how old the artifact is. N(t) = Noe where is known as the decay constant. Note that at t = 0N(t) = No, the original number of unstable nuclei. N(t) decreases exponentially with time, and as t approaches infinity, the number of unstable nuclei that remain approaches zero. Part C If a sample shows only one-fourth of its estimated original quantity of 14C, how old is it? Think about half-lives; don't try to just plug into the decay equation. (You shouldn't need to plug into it at all for this problem.) Express your answer in years to threc significant figures. Hints age years Submit My Answers Give Up

Explanation / Answer

Solving: Jack was exposed....

Given

radiation dose = 140 rem ; m = 22 g = 0.022 kg; RBE = 12

A)The amount of radiation recieved will be given by:

radiation = Radiation dose/RBE

radiation = 140/12 = 11.67 rad

Hence, Radiation recieved = 11.67 Rad

B)1 rad = 0.01 J/kg

So, 11.67 rad = 0.01 x 11.67 = 0.1167 J

Hence, E = 0.1167 J

C)RBE = 1.5

we have calculated, radiation recieved = 11.67 rad

radiation recieved = Radiation dose/RBE

Radiation dose = radiation recieved x RBE

Radiation dose = 11.67 x 1.5 = 17.51 rem

Hence, Radiation dose = 17.51 rem

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