OSMT (Ontario Society of Medical Technologists) Practice Exam

Where are the objectives seen on most microscopes often set at?

1. X 10, X 50, X 100

2. X 10, X 40, X 100

3. X 20, X 40, X 80

4. X 100, X 400, X 800

The correct answer is: X 10, X 40, X 100

The correct selection indicates that the objectives on most microscopes are typically set at magnifications of X 10, X 40, and X 100. The X 10 objective is commonly used for low power observations, allowing a wide field of view which is suitable for the examination of larger specimens or for scanning a slide. The X 40 objective serves as a mid-range magnification, providing a more detailed view of the specimen without compromising too much on the field of view. The X 100 objective, often an oil immersion lens, allows for very high magnification which is essential for observing fine details in specimens, particularly in microbiology and histology. Other sets of magnifications listed in the answer choices are less standard for conventional microscopes used in laboratory settings. While X 20 can sometimes be found in specific instruments, it is not as common in typical objectives, just as X 50 and X 80 do not represent standard choices among common microscope objectives. Therefore, the selection of X 10, X 40, and X 100 represents the most widely recognized and utilized objectives in microscopy practice.