$A$ device used for the measurement of radioactivity is

Tritium,a radioactive isotope of hydrogen,emits which of the following particles?

After the emission of one $\alpha$-particle followed by one $\beta$-particle from the atom of $_{92}X^{238}$,the number of neutrons in the atom will be

$\beta$-particles are emitted from the atom

When a $\beta $-particle is emitted from the nucleus of an element,then:

If a radioactive isotope with atomic number $A$ and mass number $M$ emits an $\alpha$-particle,the atomic number and mass number of that new isotope will become: