JEE Main & Advanced Physics Gravitation / गुरुत्वाकर्षण Question Bank Self Evaluation Test - Gravitation

  • question_answer
    In a certain region of space, gravitational field is given by\[I=-(K/r)\]. Taking the reference point to be at \[r={{r}_{0}}\]with \[V={{V}_{0}},\] find the potential.

    A) \[K\,\log \frac{r}{{{r}_{0}}}+{{V}_{0}}\]

    B) \[K\,\log \frac{{{r}_{0}}}{r}+{{V}_{0}}\]

    C) \[K\,\log \frac{r}{{{r}_{0}}}-{{V}_{0}}\]

    D) \[\log \frac{{{r}_{0}}}{r}-{{V}_{0}}r\]

    Correct Answer: A

    Solution :

    [a] We know that intensity is negative gradient of potential, i.e., \[I=-(dV/dr)\]and as here\[I=-(K/r)\], so \[\frac{dV}{dr}=\frac{K}{r},i.e.,\int{dV=Ki}\int{\frac{dr}{r}}\] or \[V-{{V}_{0}}=K\log \frac{r}{{{r}_{0}}}\] so \[V=K\log \frac{r}{{{r}_{0}}}+{{V}_{0}}\]


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