Chapter 30, Problem 21Q

To determine

The particle released when a photon strikes lithium along with alpha particle

Answer to Problem 21Q

Solution:

Helium 3. When a photon strikes lithium, it releases alpha particle and helium

Explanation of Solution

When a photon strikes lithium, it gives

${}_{\text{3}}{}^{\text{6}}\text{L}\text{i}+{}_{\text{1}}{}^{\text{1}}\text{p}\to {}_{\text{2}}{}^{\text{4}}\alpha +{}_{\text{2}}{}^{\text{3}}\text{H}\text{e}$

From above equation there are a total of 4 protons and 3 neutrons in the reactant particles. The alpha particle has 2 protons and 2 neutrons, and other product particle must have 2 protons and 1 neutron. Hence the other particle must be of helium. Only helium has protons.