If the surface charge density of an infinite sheet increases by 25%, the electric field intensity:
- A. Increases by 25%
- B. Increases by 50%
- C. Decreases by 25%
- D. Remains the same
Explanation
The field of an infinite charged sheet is the surface charge density divided by twice the permittivity, so it is directly proportional to that density and rises by the same 25 per cent. Notably the field does not depend on distance from the sheet at all, which is what makes the infinite sheet such a useful idealisation. A point charge behaves quite differently, falling off as the inverse square.
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