Question

Consider the following reaction
${}_1^{1}H+{}_1^{3}H\to {}_1^{2}H+{}_1^{2}H$
The atomic masses are given as
$m\left({}_1^{1}H\right)=1.007825u$
$m\left({}_1^{2}H\right)=2.014102u$
$m\left({}_1^{3}H\right)=3.016049u$
The $Q$ - value of the above reaction will be

• A. -4.03 MeV
• B. -2.01 MeV
• C. 2.01 MeV
• D. 4.03 MeV

Answer 1

Answer: (A)

${}_1^{1}H+{}_1^{3}H\to {}_1^{2}H+{}_1^{2}H$
The $Q$ -value of the above reaction is
$Q=\Delta M{c}^2=[1.007825+3.016049-2\times 2.014102]u\times c^2$
$=-4.33\times 10^{-3}u\times c^2$
$\because 1u=931MeV/c^2$
$\therefore Q=-4.33\times 10^{-3}\times 931MeV$
$=-4.03MeV$