Question

A positron has the same as an an electron $(9\times {10}^{-31}kg)$ but an opposite charge. When the two particles encounter each other, annihilation occurs and only gamma-rays are produced. How much energy is produced?

• A. no energy is released
• B. $7.29\times {10}^{-13}kJ$
• C. $8.1\times {10}^{-14}kJ$
• D. $1.62\times {10}^{-13}kJ$

Answer 1

The correct option is D $1.62\times {10}^{-13}kJ$

As we know, $\Delta E=m{c}^2$

So energy release will be $E=2\times 9\times {10}^{-31}\times (3\times {10}^8)=1.62\times {10}^{-13}kJ$