In a nuclear reactor,the chain reaction is controlled by introducing:

Let $m_p$ be the mass of a proton,$m_n$ that of a neutron,$M_1$ that of a $_{10}^{20}Ne$ nucleus,and $M_2$ that of a $_{20}^{40}Ca$ nucleus. Then:

Stable nuclides are those whose $n/p$ ratio is

$_{92}U^{238}$ emits $8$ $\alpha$-particles and $6$ $\beta$-particles. The neutron/proton ratio in the product nucleus is

If radium and chlorine combine to form radium chloride,the compound is:

Which one of the following nuclear reactions is not correct?