NEET Sample Paper NEET Sample Test Paper-83

  • question_answer
    A magnetic flux \[\phi =at(\tau -t)\] through a stationary loop with a resistance R varies during the time interval\[\tau \]. The amount of heat generated in the loop during that time is (neglect inductance of loop)

    A)  \[\frac{3\,R\,{{\tau }^{3}}}{{{a}^{2}}}\]                  

    B)  \[\frac{{{a}^{3}}}{3\,R{{\tau }^{2}}}\]

    C)  \[\frac{3R\,a\tau }{4}\]             

    D)  \[\frac{{{a}^{2}}{{\tau }^{2}}}{3R}\]

    Correct Answer: D

    Solution :

    The net amount of heat generated in a small time dt is \[dQ=\frac{{{E}^{2}}}{R}dt\] \[E=\,\,-\,\frac{d\phi }{dt}=(2at\,-\,a\tau )\] \[\Rightarrow \,\,\,\,\,\,dQ=\frac{{{(2at-a\tau )}^{2}}}{R}dt\] \[Q=\int\limits_{0}^{\tau }{\frac{{{(2at-a\tau )}^{2}}}{R}}dt=\frac{{{a}^{2}}{{\tau }^{3}}}{3\,R}\]


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