Question

Which of the following demonstrates the proper use of the compound light microscope?

A. When using the oil immersion lens, we can also use the coarse adjustment knob to focus to get a clearer image.

B. We should adjust the iris diaphragm to allow more light in at higher magnifications.

C. If we are not able to get a clear image with the oil immersion lens, we should bring the high dry(40x) into position to refocus.

D. When viewing a specimen, it is ok to start focusing with the high dry lens.

Answer 1

The proper use of a compound light microscope involves adjusting the iris diaphragm to allow more light at higher magnifications (Option B), using oil with the oil immersion lens for enhanced resolution, and carefully using the fine focus knob at high magnification. The correct answer is option b.

Step-by-step explanation:

The proper use of a compound light microscope requires careful attention to adjusting the lens, light, and focus. Option B is the correct statement: We should adjust the iris diaphragm to allow more light in at higher magnifications. At higher powers, such as when using an oil immersion lens, light scattering is minimized and resolution is enhanced by placing a drop of oil between the specimen and the lens, matching the refractive indices of glass and oil. It is crucial to use the fine focus knob rather than the coarse adjustment at high magnification to avoid damaging the specimen or the lens.

When operating at high magnifications, the iris diaphragm should be adjusted to control the amount of light and achieve the best possible image contrast. Care must be taken to use oil only with the oil immersion objective and to clean it afterwards to avoid damaging the microscope.