JCECE Medical JCECE Medical Solved Paper-2005

  • question_answer
    An electric bulb is marked 100 W, 230 V. If the supply voltage drops to 115 V, what is the total energy produced by the bulb in 10 min?

    A)  30 kJ         

    B)  2D kJ

    C)  15 kJ         

    D)  10 kJ

    Correct Answer: C

    Solution :

     From Joule's law, the total energy produced by bulb is \[H=\frac{{{V}^{2}}}{R}t\] Also \[P=\frac{{{V}^{2}}}{R}\] Given, \[P=100\text{ }W,V=230\,\text{volt}\] \[\therefore \] \[R=\frac{{{(230)}^{2}}}{100}=529\,\Omega \] Hence, heat produced \[=\frac{{{V}^{2}}}{R}\times t\] or \[H=\frac{115\times 115}{529}\times 10\times 60\] \[=15\,kJ\]


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