posted by .

In a tracer method the potassium isotope 42K is used for labelling. The half life of 42K is 12.5 hours. If No is original number of atoms, how many hours will it take until only (1/1024) No Atoms remain?

Goodness.

change the prior problem to

1/1024=(1/2)^(t/12.5)

2 to the what = 1024 ?

(If you do not know instantly do this
2^x = 1024 )

x log 2 = log 1024
x = 10
so
(1/2)^10 = 1/1024
t/12.5 = 10
t = 125

## Similar Questions

1. ### caluclus homework help

(1) A toy truck travels at a rate of 0.5t ft/sec after t seconds of travel (so after 6 seconds the truck is traveling 3 ft/sec). a) Graph the speed of the truck vs. time for 0<t<10. b) Find the distance the truck has traveled …
2. ### Calculus help!

(1) A toy truck travels at a rate of 0.5t ft/sec after t seconds of travel (so after 6 seconds the truck is traveling 3 ft/sec). a) Graph the speed of the truck vs. time for 0<t<10. b) Find the distance the truck has traveled …
3. ### chemistry

Gallium-67 is used medically in tumor-seeking agents. The half-life of gallium-67 is 78.2 hours. If you begin with 36.6 mg of this isotope, what mass remains after 190 hours have passed?
4. ### chemistry

use logic and simple math to determine how long it will take for a sample of potassium- 42 to decay from 8mg to 0.25mg if the half-life of this radioactive isotope is 124 hours
5. ### Chemistry

Potassium-42 has a half life of 12.4 hours. How much of an 848 g sample of potassium-42 will be left after 62.0 hours?
6. ### Chem

Radioactive 24Na with a half-life of 14.8 hours is injected into an animal in a tracer experiment. How many hours will it take for the radioactivity to fall to 12.5% of its original intensity?
7. ### math

The radioactive isotope sodium-24 is used as a tracer to measure the rate of flow in an artery or vein. The half life of sodium-24 is 14.9 hours.Suppose that a hospital buys a sample of sodium-24 a. how much of the sample will remain …
8. ### Physics (Inside the atom)

A sample of radioactive isotope I is to be used for medical diagnosis of the kidneys. The isotope has a half-life of 8.0 days, and the sample is required to have an activity of 8 x 10^5 per second at the time it is given to the patient. …
9. ### astronomy

The isotope potassium-40 (40K) decays into the isotope argon-40 (40Ar) with a half-life of 1.25 billion years. Suppose we find a rock in which seven-eighths of the potassium-40 has decayed to become argon-40, and only one-eighth of …
10. ### chemistry

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

More Similar Questions