Compare the masses and charges of an $\alpha$-particle and a $\beta^+$ particle.
Nucleus P decays by $\alpha$-decay to give nucleus Q. Nucleus Q then decays again to produce nucleus R. The proton and nucleon numbers of P and R are shown in Fig. 6.1.
On Fig. 6.1, draw a cross (\times) to indicate Q’s proton number and nucleon number. Label the cross Q.
State the names of the particles released when Q decays to form R.
Before the $\alpha$-decay, P moves with constant velocity. After the decay, Q has speed $1.3 \times 10^5\,\text{m s}^{-1}$ at an angle of $68^\circ$ to P’s original path. The $\alpha$-particle has speed $150 \times 10^5\,\text{m s}^{-1}$ at an angle $\theta$ to that same path, as illustrated in Fig. 6.2.
Apply the principle of conservation of momentum to determine $\theta$.
Calculate the kinetic energy possessed by the $\alpha$-particle.