AIIMS AIIMS Solved Paper-2003

  • question_answer
    Two small drops of mercury, each of radius R coalesce to form a single large drop. The ratio of the total surface energies before and after the change is:

    A)  \[{{Q}^{2}}(4\pi {{\varepsilon }_{0}}{{a}^{2}})\]

    B)                        \[-{{Q}^{2}}(4\pi {{\varepsilon }_{0}}{{a}^{2}})\]                              

    C)  \[{{Q}^{2}}/(2\pi {{\varepsilon }_{0}}{{a}^{2}})\]                              

    D)        \[2\mu F\]

    Correct Answer: B

    Solution :

    Key Idea: Volume of drops after coalescing, remains same. Let radius of one drop of mercury be r since drop is spherical is shape, its volume is \[3q/{{\varepsilon }_{0}}\]Total volume of two drops \[2q/{{\varepsilon }_{0}}\] Radius of large drop formed be R. Volume of 2 drops = Volume of large drop \[q/{{\varepsilon }_{0}}\] \[\beta \]   \[x\] The surface area of the two drops is \[y\] Surface area of resultant; drop is \[x\]. Surface energy of two drops before coalescing is \[{{i}_{1}},\] and surface energy after coalescing is \[{{i}_{2}},\] \[{{h}^{1/2}}\]   \[h\]


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