Question

For samples 1, 2 and 3 determine the ND/NP ratio in the table below (calculate and enter each value to 2 decimal places - 3.454 is entered as 3.45; 12 is entered as 12.00; All values less than 1 must have a "0" in front of the decimal - 0.35, 0.50, etc.). NP is the number of parent atoms. ND is the number of daughter atoms.

Using the graph, determine the number of half-lives elapsed for each sample. (estimate each value to 1 decimal place - 1.5, 6.3, etc.)

If the half-life is 5,730 years, determine the age of the sample. (enter all values without commas - example 5,678 would be entered as 5678; calculate all values to the nearest whole number)

Answer 1

The ND/NP ratio and the number of half-lives can be calculated using the given information. The age of the sample can also be determined using the half-life.

ND/NP Ratio and Number of Half-Lives

The ND/NP ratio can be determined by dividing the number of daughter atoms (ND) by the number of parent atoms (NP). Sample 1: ND = 2000, NP = 5000, ND/NP = 0.40. Sample 2: ND = 1500, NP = 3000, ND/NP = 0.50. Sample 3: ND = 300, NP = 1200, ND/NP = 0.25.

The number of half-lives elapsed can be estimated by dividing the age of the sample by the half-life. Sample 1: Age = 11460 years, Half-life = 5730 years, Number of half-lives = 2. Sample 2: Age = 31460 years, Half-life = 5730 years, Number of half-lives = 5. Sample 3: Age = 2000 years, Half-life = 5730 years, Number of half-lives = 0.3.

To determine the age of the sample, multiply the number of half-lives elapsed by the half-life. Sample 1: Number of half-lives = 2, Half-life = 5730 years, Age = 2 * 5730 = 11460 years. Sample 2: Number of half-lives = 5, Half-life = 5730 years, Age = 5 * 5730 = 28650 years. Sample 3: Number of half-lives = 0.3, Half-life = 5730 years, Age = 0.3 * 5730 = 1719 years.