The density of a cube is measured by measuring its mass and the length of its sides. If the maximum error in the measurement of mass and length are $3\%$ and $2\%$ respectively,then find the maximum error in the measurement of the density of the cube.

$A$ silver wire has mass $(0.6 \pm 0.006) \; g$,radius $(0.5 \pm 0.005) \; mm$ and length $(4 \pm 0.04) \; cm$. The maximum percentage error in the measurement of its density will be $......\,\%$

The period of oscillation of a simple pendulum is $T = 2 \pi \sqrt{\frac{L}{g}}$. The measured value of $L$ is $1.0 \text{ m}$ using a meter scale with a minimum division of $1 \text{ mm}$,and the time for one complete oscillation is $1.95 \text{ s}$ measured using a stopwatch with a resolution of $0.01 \text{ s}$. The percentage error in the determination of $g$ will be ..... $\%$.

The period of oscillation of a simple pendulum is $T = 2\pi \sqrt{\frac{l}{g}}$. The measured value of $l$ is $20.0 \text{ cm}$ known to $1 \text{ mm}$ accuracy,and the time for $100$ oscillations of the pendulum is found to be $90 \text{ s}$ using a wristwatch of $1 \text{ s}$ resolution. The accuracy in the determination of $g$ is ........ $\%$

Why is the error in a measurement expressed with both positive and negative signs?

The potential difference across the ends of a conductor is $(30 \pm 0.3) \ V$ and the current through the conductor is $(5 \pm 0.1) \ A$. The error in the determination of the resistance of the conductor is: (in $\%$)