Physical World Units And Measurements Ques 40
40. 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: 40.(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} $
BETA
