Discussion
Why does an interferometer need a reference laser?
Answer: D
The interferogram must be sampled at exactly known path differences, and the fringes of a helium-neon laser provide a ruler far finer than any mechanical encoder. It does not illuminate the sample, align the optics or calibrate absorbance. Using a known wavelength as a length standard gives these instruments wavelength accuracy better than any dispersive design, which is why they need no external wavelength calibration. Most errors here come from carrying a result across from a neighbouring case where it does not hold.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development