Question

The highest energy a particle emitted in the decay of 238U to 234Th is 

4196 &- 4 keV. From this information and the known mass of 238U, compute 

the mass of 234Th

Answer 1

$$m_{Th}=m_{U}-m_{He}-\frac{E}{c^2}\\m_{Th}=238.05-4.00-\frac{4.274}{931.5}\\ m_{Th}=234.04\ u$$