CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2001

  • question_answer
    An electric bulb is designed to draw power \[{{P}_{0}}\]at voltage \[{{V}_{0}}.\]If the voltage is V it draws a power\[{{P}_{2}}.\]Then:

    A)  \[P={{\left( \frac{{{V}_{0}}}{V} \right)}^{2}}{{P}_{0}}\]  

    B)  \[P={{\left( \frac{V}{{{V}_{0}}} \right)}^{2}}{{P}_{0}}\]

    C)  \[P=\left( \frac{V}{{{V}_{0}}} \right){{P}_{0}}\]                 

    D) \[P=\left( \frac{{{V}_{0}}}{V} \right){{P}_{0}}\]

    Correct Answer: B

    Solution :

    As we are quite well know that the power of an electric bulbs is \[P=Vi=V\frac{V}{R}=\frac{{{V}^{2}}}{R}\]                 Hence   \[\frac{P}{{{P}_{0}}}=\frac{{{V}^{2}}}{R}\times \frac{R}{V_{0}^{2}}={{\left( \frac{V}{{{V}_{0}}} \right)}^{2}}\]                 Thus  \[P={{P}_{0}}{{\left( \frac{V}{{{V}_{0}}} \right)}^{2}}\]


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