Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Find out the surface charge density at the intersection of point x = 3 m plane and x-axis, in the region of uniform line charge of 8 nC/m lying along the z-axis in free space.

  1. A 0.424 nC m<sup>$-$2</sup> Correct answer
  2. B 4.0 nC m<sup>$-$2</sup>
  3. C 47.88 C/m
  4. D 0.07 nC m<sup>$-$2</sup>

Solution

Electric field due to wire is given by $E = {{2k\lambda } \over r}$<br><br>Electric field with surface charge density $E = {\sigma \over {{ \in _0}}}$<br><br>${{2k\lambda } \over r} = {\sigma \over {{ \in _0}}}$<br><br>$$ \Rightarrow 2{1 \over {4\pi { \in _0}}}{\lambda \over r} = {\sigma \over {{ \in _0}}}$$<br><br>$\Rightarrow {8 \over {2 \times 3.14 \times 3}} = \sigma$<br><br>$\Rightarrow \sigma = 0.424$ n Cm<sup>$-$2</sup>

About this question

Subject: Physics · Chapter: Electrostatics · Topic: Coulomb's Law

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