99 Percentile Qs Bank for JEE MainPhysicsNuclear Physics
If an electron and a positron annihiliate, then the energy released is
Options
- A3 . 2 × 10 - 13   J
- B1 . 6 × 10 - 13   J
- C4 . 8 × 10 - 13   J
- D6 . 4 × 10 - 13   J
Correct answer
B. 1 . 6 × 10 - 13   J
Step-by-step solution
The amount of energy E produced by annihilation is E = M c 2 ( as per Einstein's equation ) Now, the mass of electron and positron is equal. m e - = m e + = 9 . 1 × 10 - 31   kg Then, the energy released E = M c 2 = m e - + m e + c 2 = 2 m e - c 2 = 2 × 9 . 1 × 10 - 31 3 × 10 8 2 = 1 . 6 × 10 - 13   J