What aspect of laser beams is described as “parallel nature”?

• A. Collimated
• B. Monochromatic
• C. Coherent
• D. Converged

Answer: (A)

The term "parallel nature" refers to the characteristic of laser beams that allows them to travel in straight lines with minimal divergence over distances. This property is known as being collimated. In a collimated laser beam, the light rays emitted are nearly parallel, which means the beam retains its intensity and focus over long distances, making it highly effective for applications such as ranging, surveying, and targeting.

Understanding collimation is crucial for the proper functioning of laser devices in speed measurement. This characteristic ensures that the laser can accurately measure speeds without significant spread or distortion of the beam, leading to reliable and precise results. By contrast, other terms like monochromatic, coherent, and converged refer to different properties of lasers—monochromatic relates to the single wavelength of light emitted, coherent describes the phase relationship between the light waves, and converged typically refers to light rays coming together at a point, which is not the main attribute of laser beams at a distance.