Question

In an $\alpha$-decay the kinetic energy of $\alpha$ particle is 48 MeV and Q-value of thereaction is 50 MeV. The mass number of the mother nucleus is: (Assume that daughter nucleus is in ground state)

• A. 9
• B. 100
• C. 104
• D. None of these

Answer 1

The correct option is B 100

Given that,

Kinetic energy $K.E=48MeV$

Q value $Q=50$

We know that,

The kinetic energy is

$E=\frac{A-4}{A}\times Q......\left(I\right)$

Now, put the value in equation (I)

$48A=(A-4)50$

$48A-50A=-200$

$2A=200$

$A=100$

Hence, The mass number of the mother nucleus is $100$