Assertion (A) : Köhler illumination is designed to produce bright and uniform illumination.
Reason (R) : It is a lighting system in which the condenser focuses the image of the light source directly onto the plane of the specimen.
In the light of the above statements, choose the most appropriate answer from the options given below :
The question asks to evaluate two statements, Assertion (A) and Reason (R), regarding Köhler illumination in microscopy.
Evaluating Assertion (A)
Assertion (A) states: "Köhler illumination is designed to produce bright and uniform illumination."
- Köhler illumination is a standard technique in microscopy.
- Its primary goal is to achieve even and bright illumination across the entire field of view, optimizing image quality.
- Therefore, Assertion (A) is correct.
Evaluating Reason (R)
Reason (R) states: "It is a lighting system in which the condenser focuses the image of the light source directly onto the plane of the specimen."
- This description accurately defines critical illumination, not Köhler illumination.
- In critical illumination, the light source image is focused directly onto the specimen. This often leads to uneven illumination and glare from dust or imperfections on the light source.
- Köhler illumination involves focusing an image of the light source onto the condenser's aperture plane, and then using the condenser's field lens to create an image of the lamphouse aperture (or filament pattern) in the back focal plane of the objective, resulting in uniform specimen illumination.
- Therefore, Reason (R) is incorrect.
Conclusion
Since Assertion (A) is correct and Reason (R) is incorrect, the most appropriate choice is that (A) is correct but (R) is not correct.
Important Questions from Miscellaneous
- Which of the following scheduler/schedulers is/are also called CPU scheduler ?
(A). Short Term Scheduler
(B). Long Term Scheduler
(C). Medium Term Scheduler
(D). Asymmetric Scheduler
Choose the correct answer from the options given below: - A situation where two or more processes are blocked, waiting for resources held by each other is called:
- External fragmentation occurs ________.
- Which disk scheduling algorithm looks for the track closest to the current head position?
- Which CPU scheduling algorithm prefers the process with the shortest burst time?
