NEET Sample Paper NEET Sample Test Paper-75

  • question_answer
    The electric potential at a point in free space due to charge Q Coulomb is Q X K^V. The electric field at that poi is

    A)  \[4\pi  {{\varepsilon }_{0}} Q \times  1{{0}^{22}}\,V/m\]         

    B)  \[4\pi  {{\varepsilon }_{0}} Q \times  1{{0}^{20}}\,V/m\]

    C)  \[12\pi  {{\varepsilon }_{0}} Q \times  1{{0}^{22}}\,V/m\]        

    D)  \[12\pi  {{\varepsilon }_{0}} Q \times  1{{0}^{20}}\,V/m\]

    Correct Answer: A

    Solution :

    As electric potential \[V=\frac{1}{4\pi {{\varepsilon }_{0}}}\,\frac{Q}{r}\] Given,             \[V=Q\times {{10}^{11}}\,V\] So,                   \[\frac{1}{4\pi {{\varepsilon }_{0}}}\,\,\frac{Q}{r}=Q\times {{10}^{11}}\,V\] \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{1}{r}=4\pi {{\varepsilon }_{0}}\,\,{{10}^{11}}\,\,V\] Now, electric field      \[E=\frac{V}{r}=Q\times {{10}^{11}}\times 4\pi \,{{\varepsilon }_{0}}\,{{10}^{11}}\] \[=\,\,\,4\pi \,{{\varepsilon }_{0}}Q\times {{10}^{22}}\]


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