Neutron decay in free space is given as follows:
$_0n^1 \to _1H^1 + _{-1}e^0 + [\,\,]$
Then the particle in the bracket is:

When $_{90}Th^{238}$ transforms into $_{83}Bi^{222}$,the number of $\alpha$ and $\beta$ particles emitted are:

$A$ nucleus $_Z{X^A}$ emits $9 \alpha$-particles and $5 \beta$-particles. The ratio of total protons to neutrons in the final nucleus is:

Assertion: ${}^{90}Sr$ from the radioactive fallout of a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells.
Reason: The energetic $\beta$-particles emitted in the decay of ${}^{90}Sr$ damage the bone marrow.

In the uranium radioactive series,the initial nucleus is ${ }_{92}^{238} U$ and the final nucleus is ${ }_{82}^{206} Pb$. When the uranium nucleus decays into lead,the number of $\alpha$-particles and $\beta$-particles emitted are

Which of the following interactions is responsible for beta decay?