Question

The breadth of a thin rectangular sheet is measured as $10.1cm$. The approximate error in the measurement is

• A. $\pm 1\%$
• B. $\pm 0.5\%$
• C. $\pm 0.1\%$
• D. $\pm 5\%$

Answer 1

Answer: (A)

$\pm 1\%$

The measurement of any physical quantity by any measuring instrument contains some uncertainity, this uncertainity is called error.

Here the uncertainity digit is $0.1$

So the length can be $9.9,10.0or\mathrm{10.1...}$

Taking average value, we get $10.0$

Now we can calculate the percentage error as,

$Percentageerror=\frac{Uncertainitydigit}{Averagevalue}\times 100$

$=\frac{0.1}{10}\times 100=1\%$

The error value can be positive or negative. So,

Approximate error $=\pm 1\%$