For Gauss's law, mark the correct statements (s).

Options

A. If we displace the enclosed charges (within a Gaussian surface) without crossing the boundary, then both `vecE` and `phi` remain same.
B. If we displace the enclosed charges without crossing the boundary, then `vecE` changes but `phi` remains the same.
C. If the charge crosses the boundary, then both `vecE` and `phi` would change.
D. If we charge the boundary, then `phi` changes but `vecE` remians the same.

Answer

B, C

Explanation

`phi` crossing through Gaussian surface does not depend on the location of charge , while `vec( E)` depends on it . If `q` crosses the boundary , then `q_(enclosed)` changes and hence the flux and `vec ( E)` also change.