The half-life of Radium-226 is 1590 years. What is the annual decay rate? Express the decimal result to four significant digits and the percentage to two significant digits.

Answer 1

1/2 = e^1590r where r=annual decay rate

take natural logs of both sides

ln0.5 = 1590r

divide both sides by 1590

r = ln.5/1590 = -0.69315/1590 =-0.000436=-0.04% = -0.0004 decay rate