The scanning power objective lens in a compound light microscope is the lens with the:

• A. highest magnification
• B. largest numerical aperture
• C. lowest magnification
• D. longest focal length

Answer: (C)

Verified step by step guidance

1. Understand the function of the scanning power objective lens in a compound light microscope: it is primarily used to quickly locate the specimen on the slide at a low magnification.
2. Recall that objective lenses vary in magnification, numerical aperture, and focal length, and these properties are inversely related in some cases (e.g., higher magnification lenses have shorter focal lengths).
3. Recognize that the scanning objective lens has the lowest magnification compared to other objective lenses (such as low power, high power, and oil immersion lenses), which allows for a wider field of view to easily scan the specimen.
4. Note that the scanning lens also has the longest focal length, which corresponds to the lowest magnification and allows the lens to focus on a larger area of the specimen.
5. Conclude that the correct characteristic of the scanning power objective lens is the lowest magnification, not the highest magnification or largest numerical aperture.