Question

$\beta$-particles is emitted from the nucleus of mass number A with velocity v. Then, the recoil speed of the nucleus will be

• A. $\frac{v{m}_e}{A-m_A}$
• B. $\frac{v{m}_e}{A+m_A}$
• C. $\frac{4v}{A-4}$
• D. $\frac{v}{A}$

Answer 1

The correct option is A $\frac{v{m}_e}{A-m_A}$

$v.m_e=(A-m_e)v^{\prime }$ or $v^{\prime }=\frac{v{m}_e}{A-m_e}$