The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter nucleus is an

How are gamma rays produced?

Which of the following cannot be emitted by radioactive substances during their decay?

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 to lead,the number of $\alpha$-particles emitted is .......... and the number of $\beta$-particles emitted is ..........

$A$ radioactive element $X$ emits six $\alpha$-particles and four $\beta$-particles,leading to the final product ${ }_{82}^{208} Pb$. The element $X$ is:

The radionuclide $^{11} C$ decays according to
$_{6}^{11} C \rightarrow_{5}^{11} B + e^{+} + \nu: \quad T_{1/2} = 20.3 \; min$
The maximum energy of the emitted positron is $0.960 \; MeV$. Given the mass values:
$m(_{6}^{11} C) = 11.011434 \; u$ and $m(_{5}^{11} B) = 11.009305 \; u$
Calculate $Q$ and compare it with the maximum energy of the positron emitted.