- 2 A White Lead Is A Pigment Found In Oil Paints And Can Be Used To Detect Art Forgeries In The Absence Of Radium 226 1 (136.8 KiB) Viewed 17 times
2. a. White lead is a pigment found in oil paints and can be used to detect art forgeries. In the absence of radium-226, lead-210 undergoes standard radioactive decay, dP = -KP. dt Suppose that a sample from a painting has 10 disintegrations per minute in 1970 and then shows 8.5 disintegrations per minute in 1975. Find the half-life of lead-210 and give the value of k. b. When there are impurities caused by radium-226 (which has a very long half-life), the differential equation for radioactive decay is modified to dP dt -kP+r, where r = 0.25 is source input from the radium-226 and k is from Part a. Solve this differential equation and determine the limit of P (disintegrations per minute of lead-210) as t +0.