CMC Medical CMC-Medical VELLORE Solved Paper-2009

  • question_answer
    An alpha nucleus of energy \[\frac{1}{2}m{{v}^{2}}\]bombards a heavy nuclear target of charged Ze. Then the distance of closest approach for the alpha nucleus will be proportional to

    A)  \[{{v}^{2}}\]                                     

    B)  \[1/m\]

    C)  \[1\text{/}{{v}^{4}}\]                                   

    D)  \[1/Ze\]

    Correct Answer: B

    Solution :

    Since, here nuclear target is heavy it can be assumed safely that it will remain stationary and will not move due to the. Coulombic interaction force. At distance of closest approach relative velocity of two particles is v. Here target is considered as stationary,  so \[\alpha \text{-}\]particle  comes to rest instantaneously at distance of closest approach. Let required distance is r, then from work energy-theorem. \[0-\frac{m{{v}^{2}}}{2}=-\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Ze\times 2e}{r}\] \[\Rightarrow \]               \[r\propto \frac{1}{m}\] \[\propto \frac{1}{{{v}^{2}}}\] \[\propto Z{{e}^{2}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner