What is the binding energy per nucleon (in MeV) for boron-9. The amu of the boron-9 isotope is 9.01333 amu.

8. The isotope ¹72Ta undergoes radioactive decay. After 2 hr, 1/16 of the initial amount of ¹72 Ta remains undecayed. The half-life of this isotope is A) 15 min B) 30 min C) 45 min D) 60 min

A positron and an electron annihilate each other upon colliding, thereby producing energy in the form of two gamma rays. Assuming that both gamma rays have the same energy (since both particles have the same mass), calculate the wavelength of the electromagnetic radiation used in pm. (1 pm = 10⁻¹² m; mass of electron (amu) = 0.000549)   Americium-241 is widely used in smoke detectors. Calculate the amount of americium-241 consumed in a smoke detector (initially containing 5.00 µg of Am), in micrograms, that has been used for one year if the half-life is 433 years.

A rock contains 0.697 mg of 206pb for every 1.000 mg of 238 U present. Assuming that no lead was originally present, that all the 206pb formed over the years has remained in the rock, and that the t1/2 number of nuclides in intermediate stages of decay between 238U and 206pb is negligible, calculate the age of the rock. (For 238U, 4.5x10⁹ years.) yr =