Q 11-01-034NEETJEE MainMedium
The length of a rod is measured five times as $5.62\ \text{cm}$, $5.58\ \text{cm}$, $5.65\ \text{cm}$, $5.55\ \text{cm}$ and $5.60\ \text{cm}$. The percentage error in the measurement, based on the mean absolute error, is closest to
Answer: (A) $0.5\%$
Mean value: $\bar{l} = \dfrac{5.62 + 5.58 + 5.65 + 5.55 + 5.60}{5} = \dfrac{28.00}{5} = 5.60\ \text{cm}$
Absolute errors: $0.02,\ 0.02,\ 0.05,\ 0.05,\ 0.00$
Mean absolute error: $\Delta\bar{l} = \dfrac{0.14}{5} = 0.028\ \text{cm}$
Percentage error: $\dfrac{0.028}{5.60}\times 100 = 0.5\%$
Solution by Sreeraj P, M.Sc Physics