Physical World Units and Measurements - Result Question 43
44. A student measured the diameter of a small steel ball using a screw gauge of least count $0.001 cm$. The main scale reading is $5 mm$ and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of $-0.004 cm$, the correct diameter of the ball is [2018]
(a) $0.521 cm$
(b) $0.525 cm$
(c) $0.529 cm$
(d) $0.053 cm$
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Answer:
Correct Answer: 44. (c)
Solution:
- (c) Diameter of the ball
$ \begin{aligned} & =MSR+CSR \times(\text{ least count })-\text{ zero error } \\ & =0.5 cm+25 \times 0.001-(-0.004) \\ & =0.5+0.025+0.004=0.529 cm \end{aligned} $
