Manipal Medical Manipal Medical Solved Paper-2007

  • question_answer
    . In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is\[R,\] the resistance of a 60 W bulb for use in USA will be

    A)  \[R\]

    B)  \[2R\]

    C)  \[\frac{R}{4}\]

    D)  \[\frac{R}{2}\]

    Correct Answer: C

    Solution :

     Since, power rating of bulb in both the countries India and USA should be same, so \[\frac{V_{1}^{2}}{{{R}_{1}}}=\frac{V_{2}^{2}}{{{R}_{2}}}\] \[\Rightarrow \] \[\frac{220\times 220}{{{R}_{1}}}=\frac{110\times 110}{{{R}_{2}}}\] \[\Rightarrow \] \[\frac{{{R}_{2}}}{{{R}_{1}}}=\frac{110\times 110}{220\times 220}\] \[\Rightarrow \] \[{{R}_{2}}=\frac{R}{4}\] \[(\because {{R}_{1}}=R)\]


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