The most accurate reading of the length of a $6.28 \,cm$ long fibre is ............... $cm$.

The error in the measurement of the radius of a sphere is $1\%$. The error in the calculated value of its volume is ......... $\%$

Using the expression $2 d \sin \theta = \lambda$,one calculates the values of $d$ by measuring the corresponding angles $\theta$ in the range $0^{\circ}$ to $90^{\circ}$. The wavelength $\lambda$ is exactly known and the error in $\theta$ is constant for all values of $\theta$. As $\theta$ increases from $0^{\circ}$:

Find the relative error in $Z$,if $Z = \frac{A^{4} B^{1/3}}{C D^{3/2}}$.

Can error be completely eliminated?

The length of a rod is $(11.05 \pm 0.05) \ cm$. What is the length of two such rods?