Question

A nucleus with mass number 220 initially at rest emits an $\alpha$ - particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of $\alpha$-particle.

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

Answer 1

Answer: (B)

5.4 MeV

Answer 2

$K_1 + K_2 = 5.5 \, MeV$ From ebnservation of linear momentum $[2K_1 (216 m)]^{1/2} = [2K_2(4m)]^{1/2}$ $K_2 = 54 \, K_1$ From the above $K_2 = 5.4 \, MeV$