Which expression is a valid Microscope Constant?

Which expression is a valid Microscope Constant?

• A. Ac/Af
• B. 385/.00785
• C. 49,044
• D. All of the above

Answer: (D)

A Microscope Constant is the conversion factor that turns counts you obtain under the microscope into a representative concentration for the whole sample by tying the area you examined to the total area available. One way to express this factor is the ratio of the counted area to the total area being considered, Ac/Af. You can also get the same constant by computing it numerically, such as 385 divided by 0.00785, which yields the same value as the area ratio. That calculation comes out to about 49,044, a number that represents the same scaling factor in numeric form. Because each form—Ac/Af, the numerical division, and the resulting constant value—expresses the same conversion factor, all are valid Microscope Constants.

A Microscope Constant is the conversion factor that turns counts you obtain under the microscope into a representative concentration for the whole sample by tying the area you examined to the total area available. One way to express this factor is the ratio of the counted area to the total area being considered, Ac/Af. You can also get the same constant by computing it numerically, such as 385 divided by 0.00785, which yields the same value as the area ratio. That calculation comes out to about 49,044, a number that represents the same scaling factor in numeric form. Because each form—Ac/Af, the numerical division, and the resulting constant value—expresses the same conversion factor, all are valid Microscope Constants.