JEE PYQ: Nuclear Physics Question 17
Question 17 - 2020 (06 Sep Shift 2)
Given the masses of various atomic particles $m_p = 1.0072$ u, $m_n = 1.0087$ u, $m_e = 0.000548$ u, $m_{\bar{\nu}} = 0$, $m_d = 2.0141$ u, where p $\equiv$ proton, n $\equiv$ neutron, e $\equiv$ electron, $\bar{\nu} \equiv$ antineutrino and d $\equiv$ deuteron. Which of the following process is allowed by momentum and energy conservation?
(1) $n + n \to$ deuterium atom (electron bound to the nucleus)
(2) $p \to n + e^+ + \bar{\nu}$
(3) $n + p \to d + \gamma$
(4) $e^+ + e^- \to \gamma$
Show Answer
Answer: (3)
Solution
For the momentum and energy conservation, mass defect ($\Delta m$) should be positive. Since some energy is lost in every process. $(m_p + m_n) > m_d$
BETA
