Question

1. You find an old 60Co source in the physics lab that is labeled 4.00 mCi. When you test it, you find out that its activity is now 4.85×107 Bq.

a. What is its current activity in mCi?

b. How long ago did it actually have a 4.00 mCi activity?

2. Use the following data to determine the chemical atomic mass of neon, to two decimal places.

Mass number (A) 20, 21, 22 Atomic mass (u)19.992435, 20.993841, & 21.991383 Natural abundance (%) 90.48, 0.27, & 9.25

3. Calculate the binding energy per nucleon (in MeV, to 3 sig figs) for 14N whose mass is 14.003074 u.

Answer 1