BHU PMT BHU PMT (Screening) Solved Paper-2008

  • question_answer
    Assuming that about 20 MeV of energy is released per fusion reaction \[_{1}{{H}^{2}}{{+}_{1}}{{H}^{3}}{{\to }_{0}}{{n}^{1}}{{+}_{2}}H{{e}^{4}}\] then the mass of\[_{1}{{H}^{2}}\]consumed per day in a fusion reactor of power 1 MW will approximately be

    A)  0.001 g                

    B)  0.1 g

    C)  10.0 g                                  

    D)  1000 g

    Correct Answer: B

    Solution :

                     Energy produced, \[U=Pt\] \[={{10}^{6}}\times 24\times 36\times {{10}^{2}}\] \[=24\times 36\times {{10}^{8}}J\] Energy released per fusion reaction \[=20\text{ }MeV\] \[=20\times {{10}^{6}}\times 1.6\times {{10}^{-19}}\] \[=32\times {{10}^{-13}}J\] Energy released per atom of\[_{1}{{H}^{2}}\] \[=32\times {{10}^{-13}}J\] Number of\[_{1}{{H}^{2}}\]atoms used                 \[=\frac{24\times 36\times {{10}^{8}}}{32\times {{10}^{-13}}}\]                 \[=27\times {{10}^{21}}\] Mass of\[6\times {{10}^{23}}\]atoms\[=2g\] \[\therefore \] Mass of\[27\times {{10}^{21}}\]atoms \[=\frac{2}{6\times {{10}^{23}}}\times 27\times {{10}^{21}}=0.1g\]


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