Which of the following components are essential for a bright-field microscope to view a specimen?

• A. Electron gun, magnetic coils, and fluorescent screen
• B. Light source, condenser, objective lens, and ocular lens
• C. Laser source, pinhole aperture, and photomultiplier tube
• D. Polarizer, analyzer, and phase plate

Answer: (B)

Verified step by step guidance

1. Understand the purpose of a bright-field microscope: it uses visible light to illuminate the specimen and magnify the image for viewing.
2. Identify the essential components for bright-field microscopy: a light source to illuminate the specimen, a condenser to focus the light onto the specimen, an objective lens to collect and magnify the light coming from the specimen, and an ocular lens (eyepiece) to further magnify the image for the viewer.
3. Recognize that components like an electron gun, magnetic coils, and fluorescent screen are part of electron microscopes, not bright-field microscopes.
4. Note that laser sources, pinhole apertures, and photomultiplier tubes are typically used in confocal or fluorescence microscopy, which differ from bright-field microscopy.
5. Understand that polarizers, analyzers, and phase plates are used in specialized microscopy techniques such as polarized light microscopy or phase-contrast microscopy, not in standard bright-field microscopy.