2. Solved Papers
  3. J & K CET Medical

J & K CET Medical J & K - CET Medical Solved Paper-2006

  • question_answer
    An electric bulb is rated at 220 V, 200 W. Power consumed by it when operated at 110 V is:

    A)  25 W                                    

    B)  50 W

    C)  75 W                                    

    D)  90 W

    Correct Answer: B

    Solution :

                     From Joule's law, the power consumed by bulb of resistance R is\[P=\frac{{{V}^{2}}}{R}.\]where V is potential difference. Given,   V= 220 volt, P=200W \[\therefore \]  \[R=\frac{{{V}^{2}}}{P}=\frac{220\times 220}{200}=242\,\Omega \] When,   V = 110 volt, R = 242 Q                 \[P=\frac{110\times 110}{242}=50\,W\]


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