Question:
To determine refractive index of glass slab using a travelling microscope, minimum number of readings required are :
To determine refractive index of glass slab using a travelling microscope, minimum number of readings required are :
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Recall the three focusing positions of the travelling microscope in the apparent-depth experiment.
Updated On: Nov 11, 2026
- Two
- Three
- Four
- Five
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The Correct Option is B
Solution and Explanation
In the apparent-depth method, the microscope is focused on (i) the ink mark/cross on the paper with no slab, (ii) the same mark seen through the slab (apparent position), and (iii) lycopodium powder sprinkled on the top surface of the slab.
Real thickness = reading (iii) - reading (i); apparent thickness = reading (iii) - reading (ii); \(\mu = \frac{\text{real depth}}{\text{apparent depth}}\). Thus a minimum of three readings is needed.
Answer: (2) Three
Real thickness = reading (iii) - reading (i); apparent thickness = reading (iii) - reading (ii); \(\mu = \frac{\text{real depth}}{\text{apparent depth}}\). Thus a minimum of three readings is needed.
Answer: (2) Three
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