How many inches is equivalent to one circular mil?

A circular mil is a unit of area used primarily in the electrical industry to denote the cross-sectional area of a circular conductor. Specifically, one circular mil is defined as the area of a circle with a diameter of one mil (one thousandth of an inch).

To clarify, since the diameter is one mil, the radius would be half of that, which is 0.0005 inches. The area (A) of a circle is calculated using the formula (A = \pi r^2). By substituting the radius into the equation, the area in circular mils results in:

[ A = \pi (0.0005)^2 = \pi (0.00000025) \text{ square inches} ]

This area equates to one circular mil, confirming that one circular mil represents an area of ( \frac{\pi}{1000000}) square inches.

Thus, expressing one circular mil in terms of inches, its equivalent is 0.001 square inches, leading to the conclusion that the choice stating one circular mil is equivalent to 0.001 inches is indeed accurate.