Search results
Results from the WOW.Com Content Network
Potassium-40 (40 K) is a radioactive isotope of potassium which has a long half-life of 1.25 billion years. It makes up about 0.012% (120 ppm ) of the total amount of potassium found in nature. Potassium-40 undergoes three types of radioactive decay .
All other potassium isotopes have half-lives under a day, most under a minute. The least stable is 31 K, a three-proton emitter discovered in 2019; its half-life was measured to be shorter than 10 picoseconds. [5] [6] Stable potassium isotopes have been used for several nutrient cycling studies since potassium is a macronutrient required for ...
half-life 10 −9 seconds helium-2 <1 lithium-12 <10 boron-18: 26 ... 2.40 curium-241: 32.8 2.83 ... potassium-40: 1.251 39.5 uranium-238: 4.468
t 1/2 is the half-life of 40 K; K f is the amount of 40 K remaining in the sample; Ar f is the amount of 40 Ar found in the sample. The scale factor 0.109 corrects for the unmeasured fraction of 40 K which decayed into 40 Ca; the sum of the measured 40 K and the scaled amount of 40 Ar gives the amount of 40 K which was present at the beginning ...
From January 2008 to December 2012, if you bought shares in companies when Edward B. Rust, Jr. joined the board, and sold them when he left, you would have a 23.5 percent return on your investment, compared to a -2.8 percent return from the S&P 500.
Larry Mullen Jr. is opening up about a recent diagnosis. The drummer for U2, 63, revealed in an interview with Times Radio that he's been diagnosed with dyscalculia, which makes it challenging for ...
A further 10 nuclides, platinum-190, samarium-147, lanthanum-138, rubidium-87, rhenium-187, lutetium-176, thorium-232, uranium-238, potassium-40, and uranium-235 have half-lives between 7.0 × 10 8 and 4.83 × 10 11 years, which means they have experienced at least 0.5% depletion since the formation of the Solar System about 4.6 × 10 9 years ...
Consumers are urged to destroy the recalled cucumbers, which were distributed in 26 states around the U.S.