The half-life of radium is about 1600 years and its atomic number is 226. Calculate (i)  the percentage of undecayed atoms left after 100 years. (ii)  the activity of 1 mg of radium (assume one disintegration/atom)

We obviously cannot wait for 4 million years to determine the half-life of technetium, or even 87.7 years to determine the half-life of plutonium. The half-life of a substance is determined using a Geiger counter, which is essentially a tube filled with an inert gas. When a particle decays and produces radiation, it briefly ionizes the gas and produces a detectable electric pulse, which is amplified and counted by a detector (before digital displays were available, you would hear clicks and see a needle register on a dial). Determine the formula for the half-life of a substance, H(M), with an initial count of N0 pulses and a count of N1 pulses M minutes later.

The half-life for the decay of carbon-14 is 5.73*10^3 years. Suppose the activity due to the radioactive decay of the carbon-14 in a tiny sample of an artifact made of wood from an archeological dig is measured to be 1.0*10^ 3Bq. The activity in a similar-sized sample of fresh wood is measured to be 6.9*10^3 Bq. Calculate the age of the artifact. Round your answer to 2 significant digits.

Radium-226, the first radioactive isotope used for its radioactive properties, has a half life of 23.0 centuries. How long does it take in centuries for this isotope to degrade by 30.6%? (the answer should be entered with 3 significant figures; do not enter units; give answer in normal notation--examples include 1.23 and 120. and -123 and 123. and 12.3)

3. (a) Calculate the decay constant for cobalt-60 (T1/2 = 5.26 Years) in units of week-¹ (b) Calculate the activity of a 5000-Ci cobalt-60 source after 10 years.

An 8 g sample of a radioactive element takes 8.42 million years to reduce into 2 g. Calculate the half-life and identify the element.

Tritium has a half-life of 12.33 years. What fraction of the nuclei in a tritium sample will remain after the following periods of time? (a) 4.10 yr (b) 10.8 yr (c) 123.3 yr Your response is off by a multiple of ten. (d) According to N = Ne-At, an infinite amount of time is required for the entire sample to decay. Discuss whether that is realistic.