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NEET Sample Paper NEET Sample Test Paper-30

  • question_answer
    The time required to coat a metal surface of \[800\text{ }c{{m}^{2}}\] with \[5\times {{10}^{-3}}cm\] thick layer of silver (density\[=10.5\text{ }g\text{ }c{{m}^{-3}}\]) with the passage of 3A current through a silver nitrate solution is

    A)  \[115\text{ }sec\]                   

    B)  \[125\text{ }sec\]

    C)  \[135\text{ }sec\]                   

    D)  \[145\text{ }sec\]

    Correct Answer: B

    Solution :

    Volume of \[Ag=800\times 5\times {{10}^{-3}}\text{ }c{{m}^{3}}\] Mass of \[Ag=V\times d=0.42\text{ }g\] \[A{{g}^{+}}+{{e}^{-}}\xrightarrow{{}}Ag\] \[\because \]   \[108g\]\[Ag\] require \[96500\,C\] \[\therefore \]\[0.42\,g\]\[Ag\]require \[=\frac{96500}{108}\times 0.42=375.3C\] \[t=\frac{Q}{I}=\frac{375.3}{3}=125\sec \]


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