Question

13. The length of a linear rod is measured as 20.2 cm.
The approximate error in the measurement is
(1) +or-0.5%
(2) + or-0.05%
(3) + or-5%
4) +or-1%
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Answer 1

Given that,

Length of rod = 20.2 cm

Let us suppose the least count of the scale is 0.1 cm.

$\Delta l=0.1\ cm$

We need to calculate the approximate error in the measurement

Using formula of error

$percentage\ error=\pm\dfrac{\Delta l}{l}\times100$

Where, l = original length

$\Delta l$ = least count

Put the value into the formula

$percentage\ error = \pm\dfrac{0.1}{20.2}\times100$

$percentage\ error = \pm0.5$

Hence, The approximate error in the measurement is ±0.5%.

(1) is correct option