When two resistors of resistances $R_1=(200 \pm 2) \Omega$ and $R_2=(400 \pm 4) \Omega$ are connected in series,then the equivalent resistance of the combination is

$A$ torque meter is calibrated to reference standards of mass,length,and time,each with $5 \%$ accuracy. After calibration,the measured torque with this torque meter will have a net accuracy of $............\%$.

The acceleration due to gravity is found up to an accuracy of $4\,\%$ on a planet. The energy supplied to a simple pendulum of known mass '$m$' to undertake oscillations of time period $T$ is being estimated. If the time period is measured to an accuracy of $3\,\%$,the accuracy to which $E$ is known is $..........\,\%$.

The pressure on a square plate is measured by measuring the force on the plate and the length of the sides of the plate. If the maximum percentage error in the measurement of force and length are respectively $4\%$ and $2\%$,the maximum percentage error in the measurement of pressure is ....... $\%$

Time for $20$ oscillations of a pendulum is measured as $t_1 = 39.6\, s$,$t_2 = 39.9\, s$,and $t_3 = 39.5\, s$. What is the precision in the measurements? What is the accuracy of the measurement?

$A$ set of defective observation weights is used by a student to find the mass of an object using a physical balance. $A$ large number of readings will reduce: