The error in the measurement of force acting normally on a square plate is $3 \%$. If the error in the measurement of the side of the plate is $1 \%$, then the error in the determination of the pressure acting on the plate is

In an experiment, the coefficient of viscosity (in $\mathrm{mPa} . \mathrm{s})$ of a liquid was determined as $2.62,2.68,2.58$, $2.57,2.54$ and 2.55 . The mean absolute error in the determination of the coefficient of viscosity of the liquid is

A piece of length 3.532 m is cut from a rod of length 43.4 m . The length of the remaining rod in metre is (up to correct significant figures)

If the length of a rod is measured as 830600 mm , then the number of significant figures in the measurement is