Some nucleus of 74X189 (atomic mass = 188.96191 u) undergoes - decay to become 75X189 (atomic mass = 188.95922 u). What is the energy (in MeV) released in this process?

To determine the energy released in this process, we first need to find the mass difference between the initial and final nuclei. This mass difference can then be used to calculate the energy released using Einstein's famous equation, E = mc^2, where E is the energy, m is the mass difference, and c is the speed of light.

1. Find the mass difference:
The atomic mass of the initial nucleus (74X189) is given as 188.96191 u, and the atomic mass of the final nucleus (75X189) is given as 188.95922 u. To find the mass difference, subtract the final mass from the initial mass:

Mass difference = Initial Mass - Final Mass
= 188.96191 u - 188.95922 u

2. Convert the mass difference to kilograms:
Remember that 1 atomic mass unit (u) is approximately equal to 1.66 × 10^-27 kilograms (kg). Multiply the mass difference by the conversion factor to obtain the mass difference in kilograms:

Mass difference (kg) = Mass difference (u) x (1.66 × 10^-27 kg/u)

3. Calculate the energy released:
Now that we have the mass difference in kilograms, we can calculate the energy released using Einstein's equation:

Energy (Joules) = mass difference (kg) x (speed of light)^2
Energy (Joules) = Mass difference (kg) x (299,792,458 m/s)^2

4. Convert the energy from Joules to electronvolts (eV):
Finally, convert the energy from Joules to electronvolts by using the conversion factor that 1 electronvolt is equivalent to 1.602 × 10^-19 Joules.

Energy (eV) = Energy (Joules) / (1.602 × 10^-19 J/eV)

Since the question asks for the answer in MeV (million electronvolts), divide the energy in eV by 10^6:

Energy (MeV) = Energy (eV) / 10^6

By following these steps, you should be able to determine the energy released in this decay process.