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NEET Sample Paper NEET Sample Test Paper-76

  • question_answer
    How much time is required to do the electroplating of Ag layer on a coffee tray \[\left( 30\,\,cm \times 15\,cm \right)\] to a thickness of 1 mm using a constant current of 1.0 A. Given that density of Ag is\[10.5 g/c{{m}^{3}}\].

    A)  7720 sq                       

    B)  120 min             

    C)  772 s               

    D)  77.2 s

    Correct Answer: A

    Solution :

    Volume of Ag metal required to coat the coffee tray \[=\,\,\,30\times 15\times 2\times 0.1 =90 c{{m}^{3}}\] \[\operatorname{Mass} of Ag required =\,\,\frac{Volume\,\,of\,\,Ag}{Density\,\,of\,\,Ag}\] \[=\,\,\,\frac{90}{10.5}=8.57\,\,g\] Gram equivalent of \[\operatorname{Ag} = \,\frac{8.57}{108} = 0.08\] \[Number of Faraday passed = 0.08\] Number of Coulomb?s passed \[= \,0.08 \times  96500\] \[=\,\,\,7720 C\]\[\operatorname{time} = 7720 s\]


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