NEET Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर NEET PYQ-Current Electricity Charging Capacitors

  • 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:                                  [AIPMT (S) 2004]

    A) \[R\]     

    B)                   \[2R\]

    C)  \[\frac{R}{4}\] 

    D)                   \[\frac{R}{2}\]

    Correct Answer: C

    Solution :

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


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