Final answer:
Optical microscopes in physicians' office laboratories typically have three or four objectives to allow viewing of samples at various magnifications.
Step-by-step explanation:
The optical microscopes used in physician's office laboratories usually have three or four objectives. These objectives are critical components of a compound microscope, contributing to different magnification levels necessary for various examinations. Microscopes in these settings are designed to be versatile and user-friendly, providing clear images of specimens at multiple magnifications. The number of objectives can vary, but three to four is typical for standard laboratory use, enabling physicians to view samples at low, medium, and high magnifications.