When using a compound light microscope, you should begin viewing a specimen with which objective lens?

• A. Low power objective (10x)
• B. Scanning objective (4x)
• C. Oil immersion objective (100x)
• D. High power objective (40x)

Answer: (B)

Verified step by step guidance

1. Understand the purpose of each objective lens on a compound light microscope: the scanning objective (4x) is used for initially locating the specimen, the low power objective (10x) provides a closer view, the high power objective (40x) offers more detail, and the oil immersion objective (100x) is for the highest magnification with oil to improve resolution.
2. Recognize that when starting to view a specimen, it is important to use the lens that provides the widest field of view and the lowest magnification to easily locate the area of interest on the slide.
3. Identify that the scanning objective lens (4x) has the lowest magnification and the widest field of view among the options, making it the best choice for initially finding the specimen.
4. After locating the specimen with the scanning objective, you can then switch to higher magnification lenses (such as 10x, 40x, or 100x) to observe finer details.
5. Therefore, the correct procedure is to begin viewing a specimen with the scanning objective lens (4x) before moving to higher magnifications.