The Half-Life Of Cesium-137 Is 30 Years. Suppose We Have A 40 Mg Sample. Find The Mass That Remains After T Years. Step 1 Let Y(T) Be The Mass (In Mg) Remaining After T Years. Then We Know The Following. Y(T) = Y(0)Ekt = Ekt Since The Half-Life Is 30 Years, Then Y(3) = Mg. How Much Of The Sample Remains After 20 Years? After 20 Years We Have The

 

 

 

The half-life of cesium-137 is 30 years. Suppose we have a 40 mg sample. Exercise (a) Find the mass that remains after t years. Step 1 Let y(t) be the mass (in mg) remaining after t years. Then we know the following. y(t) = y(0)ekt -40 40 ekt Step 2 Since the half-life is 30 years, then y(30) Submit Skip (you cannot come back) Exercise (b) How much of the sample remains after 20 years? Step 1 After 20 years we have the following. mg. -4/3X y(20) 40-2 mg (Round your answer to two decimal places.) Submit Skip (you cannot come back) Exercise (c) After how long will only 1 mg remain? Step 1 To find the time at which only 1 mg remains, we must solve 1 = y(t) = 40(2-t/30), and so we get the following. t = -30 log2