Question 19

The length of the oval is 100 micrometers.

The length of the oval is determined by the number of divisions it spans on the ocular micrometer, with each division representing 25 micrometers. Given that the oval measures 4 divisions, the calculation yields a total length of 100 micrometers (4 divisions x 25 micrometers).

A) 500 micrometers

This option is incorrect because it suggests that the oval spans 20 divisions on the ocular micrometer. If each division equals 25 micrometers, then 20 divisions would equal 500 micrometers, which does not match the measurement context provided.

B) 200 micrometers

This option is also incorrect. A length of 200 micrometers would imply that the oval extends across 8 divisions on the ocular micrometer. However, the measurement clearly indicates a span of only 4 divisions.

C) 100 micrometers

This option is correct because it accurately reflects the measurement of the oval, which spans 4 divisions at 25 micrometers each. Thus, the total length is calculated as 4 x 25 micrometers, equating to 100 micrometers.

D) 25 micrometers

This option is incorrect as it suggests that the oval is only one division long. Given that the measurement indicates the oval spans 4 divisions, this option does not accurately represent the length.

Conclusion

The correct answer, 100 micrometers, arises from the accurate calculation based on the divisions of the ocular micrometer. All other options misinterpret the division counts, leading to incorrect total lengths. This highlights the importance of precise measurement interpretation in microscopy.