AMU Medical AMU Solved Paper-2002

  • question_answer
    1000 drops of water each of radius r and charged to a potential V coalesce together to form a big drop. The potential of big drop will be

    A)  10 V                                     

    B)  100 V

    C)  1000 V                                 

    D)  \[\frac{V}{100}\]

    Correct Answer: B

    Solution :

                     Let R be radius of big drop and r of small drop, then volume of big drop                 = 1000 \[\times \] volume of small drop                 \[\frac{4}{3}\pi {{R}^{3}}=1000\times \frac{4}{3}\pi {{r}^{3}}\] \[\Rightarrow \]               R = 10 r Potential of small drop                 \[V=\frac{1}{4\,\pi \,{{\varepsilon }_{0}}}.\frac{q}{r}\]                    ... (i) Potential of bigger drop                 \[V=\frac{1}{4\,\pi \,{{\varepsilon }_{0}}}\frac{1000\,q}{R}\]                 \[V=\frac{1}{4\,\pi \,{{\varepsilon }_{0}}}\times 1000\times \frac{q}{10\,r}\]...(ii) From Eqs. (i) and (ii), we get                 V = 100 V.


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