2) A sample of 113min has a half-life of 100. minutes. What amount of 113m In remains (in CPM) if a 10,000 CPM sample is allowed to decay for 5.0 hours?

THE AMOUNT OF THE SAMPLE REMAINING AFTER 5 HOURS IS 1250 CPM

Explanation:

A sample has a half life of 100 minutes. To solve for the amount remaining after a given amount of 10000CPM decay in 5 hours, we use the formula:

Nt = No * (1/2)^t/t1/2

Where:

Nt = amount remaining = unknown

No = initial amount = 10000 CPM

t = time elapsed for decay = 5 hours = 60*5minutes = 300 minutes

t1/2 = half life = 100 minutes

Putting the values into the formula, we have:

Nt = 10000 * (1/2)^ 300/100

Nt = 10000 * (1/2)^3

Nt = 10000 * 0.125

Nt = 1250 CPM

The amount of the sample remaining after 5 hours is 1250 CPM.

20 drops hope this