JEE PYQ: Nuclear Physics Question 20
Question 20 - 2019 (08 Apr Shift 2)
A nucleus A, with a finite de-Broglie wavelength $\lambda_A$, undergoes spontaneous fission into two nuclei B and C of equal mass. B flies in the same direction as that of A, while C flies in the opposite direction with a velocity equal to half of that of B. The de-Broglie wavelengths $\lambda_B$ and $\lambda_C$ of B and C are respectively:
(1) $\lambda_A, 2\lambda_A$
(2) $2\lambda_A, \lambda_A$
(3) $\lambda_A, \frac{\lambda_A}{2}$
(4) $\frac{\lambda_A}{2}, \lambda_A$
Show Answer
Answer: (4)
Solution
$\vec{p} = \vec{p’} + \vec{p_k}$ or $\vec{p’} = \vec{p} - \frac{\vec{p’}}{2}$ $= \frac{\vec{p}}{2}$ As $\lambda = \frac{h}{p}$ $\Rightarrow \lambda_B = \frac{\lambda_A}{2}$ and $\lambda_C = \lambda_A$
BETA
