Q1: Gratings is associated with the measurement of

ANS:A - linear displacement.

Gratings are primarily associated with the measurement of linear displacement. Explanation:

1. Linear Displacement: Gratings, also known as optical gratings or diffraction gratings, are optical devices consisting of a periodic structure with evenly spaced parallel slits or rulings. When light passes through a grating, it undergoes diffraction, resulting in the formation of multiple beams or spectral lines. By analyzing the interference patterns produced by these beams, it is possible to measure linear displacement, such as the distance between two points or the movement of an object along a straight path. Gratings are commonly used in spectrometers, interferometers, and other optical instruments for precise measurement of linear displacements.
2. Concavity/Convexity: Gratings are not specifically associated with the measurement of concavity or convexity. While diffraction gratings can be used to analyze the curvature of optical surfaces indirectly through interference patterns, their primary function is related to the dispersion and analysis of light rather than the measurement of surface curvature.
3. Surface Texture: Gratings are not directly associated with the measurement of surface texture. Surface texture measurement typically involves techniques such as profilometry, interferometry, or stylus-based instruments that directly assess the roughness, waviness, or other characteristics of a surface.
4. Flatness: Gratings are not typically used for the measurement of flatness. Flatness measurement usually involves the use of precision instruments such as flatness gauges, optical flats, or interferometers to assess the deviation of a surface from a perfectly flat plane.