The least count of a screw gauge is 0.001 cm. The reading of a measurement is 0.250 cm. How many significant figures does it have? MCQ with Answer and Explanation

The least count of a screw gauge is 0.001 cm. The reading of a measurement is 0.250 cm. How many significant figures does it have?
A. 4
B. 1
C. 2
D. 3
Answer: Option D
Solution (By JKSSB Mock Tests)
Reading 0.250 cm has three significant figures (2,5, and trailing zero after decimal). Least count gives precision, trailing zero indicates measurement to 0.001 cm, so it's significant.

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