The electric field intensity at a distance r from a point charge q is
- A. proportional to q and to r
- B. proportional to q and inversely proportional to r squared
- C. independent of r
- D. proportional to r squared
Explanation
Dividing the Coulomb force by the test charge leaves E equal to kq over r squared, so the field also obeys an inverse square law and points radially outwards for a positive charge. Field lines drawn from such a charge spread out into space, and their decreasing density with distance is a picture of the same falling intensity. For a uniform field, as between parallel plates, E is constant instead.
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