What device is used to view a virus?

The electron microscope is the correct device used to view a virus due to its ability to provide much higher resolution than light microscopes. Viruses are extremely small, often ranging from 20 to 300 nanometers, which is significantly smaller than the wavelengths of visible light. Light microscopes typically have a maximum resolution of about 200 nanometers, making them inadequate for observing such tiny structures.

In contrast, electron microscopes utilize beams of electrons instead of light, which allows for much greater magnification and resolution. This technology can achieve resolutions down to a few nanometers, enabling scientists to visualize the detailed structures of viruses, including their shape and composition.

The other devices listed, such as scanning microscopes and phase-contrast microscopes, also do not provide the necessary resolution to identify viruses effectively. Scanning microscopes, for instance, are designed primarily for examining the surface topology of samples rather than achieving the level of detail needed for viral imaging. Phase-contrast microscopes enhance the visibility of transparent specimens but still rely on light wavelengths that cannot resolve the fine details of viruses. Therefore, the electron microscope stands out as the most suitable option for this purpose.