What ocular lens magnification is commonly paired with a 40x objective lens in a compound light microscope?

The typical ocular lens magnification paired with a 40x objective lens in a compound light microscope is indeed 10x. This combination yields a total magnification of 400x, calculated by multiplying the objective lens magnification (40x) by the ocular lens magnification (10x).

This pairing is standard in many educational and laboratory settings because it offers a practical balance between clarity and detail without making the image too distorted or difficult to observe. Higher magnifications could lead to a very small field of view and can complicate focusing on specimens. Thus, the use of a 10x ocular lens maintains a suitable level of detail while still allowing for good usability in examining specimens at 40x magnification.