Visual Testing (VT) Practice Exam

To obtain light of a specific wavelength, which of the following should be used?

1. Filters

2. Shades

3. Reflectors

4. Diffractive screens

The correct answer is: Filters

The use of filters is the correct choice for obtaining light of a specific wavelength. Filters are optical devices designed to transmit specific wavelengths of light while blocking others. They work by absorbing certain wavelengths and allowing only the desired wavelength to pass through, making them essential in various applications, including photography, optical experiments, and color corrections in lighting. In contrast, shades primarily reduce the intensity of light without selectively allowing specific wavelengths to pass, which limits their utility when precise color or wavelength selection is needed. Reflectors redirect light and can enhance the intensity or focus it in a particular direction but do not filter out specific wavelengths. Diffractive screens, while useful for displaying light through diffraction patterns, are not designed to isolate specific wavelengths of light effectively like filters do. Using filters ensures that the light required for a particular application meets the necessary wavelength criteria, aiding in accurate measurements, experiments, and visual presentations.