The activity of a stock isotope is 10,000 DPM/0.10mL. If 0.25 ml of this stock is placed in 2.50 ml of water, what is the activity in the diluted specimen?
My guess is that I just multiply the 10,000 DPM by the 1/10 dilution factor. I then come up with 1,000DPM/0.10ml. Does this sound right? I am very confused
1000 is right.
To make this clear, the DPM is 1000/0.01 mL
To find the activity in the diluted specimen, you can use the concept of dilution factor.
First, let's calculate the total volume of the diluted specimen:
Total volume = Initial stock volume + Volume of water added
= 0.25 mL + 2.50 mL
= 2.75 mL
Now, let's calculate the dilution factor:
Dilution factor = Total volume of diluted specimen / Initial stock volume
= 2.75 mL / 0.25 mL
= 11
To find the activity in the diluted specimen, divide the activity of the stock isotope by the dilution factor:
Activity in the diluted specimen = Activity of stock isotope / Dilution factor
= 10,000 DPM / 11
= 909.09 DPM
So, the activity in the diluted specimen is approximately 909.09 DPM.