43Lb has a half life of 42 minutes. If you start with 100 grams...

If the half-life of a certain radioactive substance is 2000 years, estimate how many years must elap...

If 6.90 g of (half-life = 5.30 y) are allowed to decay, how many grams would be left after 1.00 y a...

What is the half-life of an isotope if it decays to 12.5% of its radioactivity in 18 minutes?

If the half-life of a 20.0g is known to be 24 minutes, how long will it take for only 5.0 grams of t...

The half-life of P-32 is 14 days. How long after a sample is delivered can a laboratory wait to use...

The half-life of Th(227) is 18.72 days. It decays by alfa emission to Ra(223), an alfa emitter whose...

What is the half-life of an isotope that decays to 50% of its original activity in 55.6 hours?

What happens to the half-life of Uranium-238 if the number of U particles in the bucket is increased...

Given that the half-life of a certain radioactive isotope is 32 hours, find the fraction of the samp...

What is half-life and how do I calculate the remaining amount of a substance after 270 days if its h...

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