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108 solutions

First Order Half Life

Q. The Cs-131 nuclide has a half-life of 30 years. After 107 years, about 3.0 grams remain. The original mass of the Cs-131 sample is closest to

Solved • Dec 11, 2019

First Order Half Life

Q. The half-life of 90-Sr is 28 years. How long will it take for a given sample of 90-Sr to be 64% decomposed?

Solved • Dec 11, 2019

First Order Half Life

Q. Consider a certain type of nucleus that has a half-life of 32 min. Calculate the percent of original sample of nuclide remaining after 1.9 hours have passed.

Solved • Dec 11, 2019

First Order Half Life

Q. The fraction of a radioactive isotope remaining at time t is (1/2) where t1/2 is the half-life. If the half-life of carbon-14 is 5730 year what fraction of carbon-14 in a piece of charcoal remains after a. 16 yr b. 1.5x104 yr c. 1.7x105 yr

Solved • Dec 11, 2019

First Order Half Life

Q. Even though plutonium-239 (t1/2 = 2.41x104 yr) is one of the main fission fuels, it is till a radiation hazard present in spent uranium fuel from nuclear power plants. How many years does it take for 67% of the plutonium-239 in spent fuel to decay?

Solved • Dec 11, 2019

First Order Half Life

Q. Ruthenium-106 ( 106Ru) is used to treat melanoma in the eye. This isotope decays by β−emission with a half-life of 373.59 days. One source of the isotope is reprocessed nuclear reactor fuel. How many years after 106 Ru is implanted in the eye does it take for its decay rate (or activity) to be reduced to 26.5% of the initial decay rate? Use 1 year =365 days.

Solved • Dec 9, 2019

First Order Half Life

Q. A moon rock collected by a US Apollo mission is estimated to be 4.40 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current mass of 206Pb in the rock, it currently contains 1.595 g of 238U? The half-life of 238U is 4.47x10^9 years. 206Pb mass: __g

Solved • Dec 6, 2019