VIT Engineering VIT Engineering Solved Paper-2014

  • question_answer
    In hydrogen discharge tube, it is observed that through a given, cross-section \[3.31\times {{10}^{15}}\] electrons are moving from right to left and \[3.12\times {{10}^{5}}\] protons are moving from left to right. The current in the discharge tube and its direction will be

    A) 2 mA, towards left

    B) 2 mA, towards right

    C) 1 mA, towards right

    D) 2 mA, towards left

    Correct Answer: C

    Solution :

    Number of electrons \[s={{\left( \frac{{{K}_{sp}}}{4} \right)}^{1/3}}={{\left( \frac{32\times {{10}^{-12}}}{4} \right)}^{1/3}}=2\times {{10}^{-4}}M\] Number of protons \[k={{\wedge }_{eq}}.C\] Now, the current is given by the relation                       \[=\left( 91{{\Omega }^{-1}}c{{m}^{2}}e{{q}^{-1}} \right)\left( \frac{2.54}{159/2\times 1000}eq.c{{m}^{-3}} \right)\]                     \[=2.9\times {{10}^{-3}}{{\Omega }^{-1}}c{{m}^{-1}}\]                     \[\frac{{{\left( {{t}_{1/2}} \right)}_{1}}}{{{\left( {{t}_{1/2}} \right)}_{2}}}={{\left[ \frac{{{a}_{2}}}{{{a}_{1}}} \right]}^{n-1}}\]                       \[\left( {{\text{t}}_{\text{1/2}}} \right)\text{=0}\text{.1s}\text{.    }{{\text{a}}_{1}}=400\] Now, due to excess the charge on electrons, the direction of the current will be towards right


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