Question

Using the tabular values of atomic masses, find the threshold kinetic energy of an alpha particle required to activate the nuclear reaction Li⁷ (α, n) B¹⁰. What is the velocity of the B¹⁰ nucleus in this case?

Answer 1

The Q of Li⁷ (α, n) B¹⁰

 Q = 2.79 MeV 

Then the threshold energy of α-particle is

The velocity of B¹⁰ in this case is simply the velocity of centre of mass

This is because both B¹⁰ and n are at rest in the CM frame at threshold. Substituting the values of various quantities 

we get v = 5.27 x 10⁶ m/s