Question

A nucleus with mass number 220 initially at rest emits an α-particle. If the Q value of the reaction is 5.5 MeV. Calculate the kinetic energy of the α-particle

• A. 4.4 MeV
• B. 5.4 MeV
• C. 5.6 MeV
• D. 6.5 MeV

Answer 1

Answer: (B)

5.4 MeV

Answer 2

Q-value of the reaction is 5.5 eV i.e. $k_{1} + k_{2} = 5.5MeV$……(i)

By conservation of linear momentum

$p_{1} = p_{2} \Rightarrow \sqrt{2(216)k_{1}} = \sqrt{2(4)k_{2}}$

⇒ k₂ = 54 k₁ ……(ii)

On solving equation (i) and (ii) we get k₂ =5.4MeV.