Q. Laser beams are used to measure long distances because
A) They are monochromatic
B) They are highly polarised
C) They are coherent
D) They have high degree of parallelism
Explanation
(d) Laser beams are perfectly parallel. So that they are very narrow and can travel a long distance without spreading. This is the feature of laser while they are monochromatic and coherent these are characteristics only
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.