AP Physics 1 Question 49: Answer and Explanation

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Question: 49

4. If T, C, M, and L represent the dimensions of time, charge, mass, and length, respectively, which of the following represents the correct dimensions for the permittivity of free space (ε0)?

  • A. T2C2/(ML3)
  • B. ML3/(T2C2)
  • C. C2M/(T2L2)
  • D. T2L2/(C2M)

Correct Answer: A


A Start with the equation for electric force, and then solve for ε0:

Next, substitute in the units for each variable:

Finally, use the letters indicated in the problem for each unit: