Five charges q1, q2, q3, q4, and q5 are fixed at their positions as shown in Fig. 1.4. S is a Gaussian surface. The Gauss’s law is given by


Which of the following statements is correct?




We know from Gauss Law that the closed surface integral of electric flux density is equal to the charge enclosed by that closed surface. This is mathematically given by




Here,



Since, the electric field lines in the given system will be from all charges q1, q2, q3, q4 and q5.



If there will be no q1, q3 and q5 charges outside the given Gaussian surface, then both the RHS and the LHS of the expression (1) will have contributions from q2 and q4 only.


Therefore, the Electric field in LHS of the expression (1) has contribution from all charges while the in the RHS of the expression (1) has contribution from charges q2 and q4 only.


Also, to make the LHS and RHS of the expression (1) equal, the box encompassing all the charges must be selected as Gaussian surface.

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