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Reviewed CSCA Physics question · Easy

在真空中，两个点电荷之间的库仑力大小为F。若将它们之间的距离增大为原来的2倍，同时保持电荷量不变，则库仑力变为多少？

  1. F/4
  2. F/2
  3. 2F
  4. 4F
Show the answer and explanation

Correct answer

A. F/4

Principle or equation

库仑定律：F = k q1 q2 / r²。

Why this answer is correct

距离变为2r，则F' = k q1 q2 / (2r)² = F/4。

Example

若F=8 N，距离加倍后F'=2 N。

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