NEET Sample Paper NEET Sample Test Paper-77

  • question_answer
    If a particle of mass m and charge q is thrown at a speed u against a uniform electric field E. The distance that it will travel before coming to momentary rest is

    A)  \[\frac{m{{u}^{2}}}{2qE}\]               

    B)  \[\frac{mu}{qE}\]

    C)  \[\frac{qE}{m}\]                                  

    D)  None of these

    Correct Answer: A

    Solution :

    Particle is thrown against electric field \[\therefore \,\,\,\,\,\operatorname{Re}tardation\,\,is\,\,a=-\frac{F}{m}\] \[=-\frac{qE}{m},\,\,(\left| F \right|\,\,=\,\,q\,E)\] Now,    \[{{\operatorname{v}}^{2}}- {{u}^{2}}= 2as\] \[\Rightarrow \,\,\,\,\,0-{{u}^{2}}=2\frac{(-\,qE)}{m}\,\,s\,\,\Rightarrow \,\,s=\frac{m{{u}^{2}}}{2qE}\]


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